Chunzhi Li

Junyong Yan

Design Method and Implementation of Ternary Logic Optical Calculator 

Keywords: ] Design Criterion, Ternary Logic, Reconfigurable, Ternary Optical Computer, Optical Calculator

Compared with the conventional electronic computer, the Ternary Optical Computer (TOC) is the better idea for next generation computing tools because it possesses numerous data bits, enough intercom bandwidth, and inter controller made of electronic computer, but when designing optical calculators in TOC, there is much randomness that bring the manufacture of the optical calculators on lots of difficulties. In order to clear up the randomness, we have analyzed various designs of the optical calculators. In this research, a new rule, named the Decrease-Radix Design, was founded. According to the rule we established a design criterion for multivalued logic calculator which includes eight steps. According to the criterion, all ternary logic optical calculators can be designed by a few basic units and the calculators have clear structures. It is possible to reconstruct any ternary logic optical calculator with the same basic units group by virtue of the criterion. Followed the design criterion, a hundreds-bit reconfigurable ternary logic optical calculator has been designed till June, 2007. In this paper we introduce the Decrease-Radix Design rule and the design criterion of multi-valued logic calculator in detail, and also introduce the design, manufacture and the experiment of the hundreds-bit reconfigurable ternary logic optical calculator. In the end, some photos of the optical calculator and its experiment will be shown.

Introduction

The Ternary Optical Computer(TOC) Principle [START_REF] Yi | Ternary Optical Computer Principle[END_REF][2] [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF][5] [START_REF] Yi | Ternary Optical Computer Architecture[END_REF], presented by Prof. Yi Jin in 2002, in which information was expressed with no light state and two perpendicular polarization directions light (such as the vertical polarization light and the horizontal polarization light) and the three optical states can be transformed each other using liquid crystal and polarizer, is a bran-new idea for next generation computing tools because that it possesses of numerous data bits, enough intercom bandwidth, and inter controller made of electronic computer. After that, lots of experiments on TOC were conducted. The researchers in this area have carried out a series of experiments on the design and the manufacture of some important components, i.e. the ternary optical encoder [START_REF] Hao | Research on Principle of Coder and Decoder in Ternary Optical Computer by Experiment[END_REF][9] [START_REF] Weigang | Design and Implementation of the 100-Bit Coder for Ternary Optical Computers[END_REF], ternary optical decoder [START_REF] Hao | Research on Principle of Coder and Decoder in Ternary Optical Computer by Experiment[END_REF] [START_REF] Junyong | Study on the Feasibility of Coding and Decoding Multi-bit Ternary Optical Signal Used in Ternary Optical Computer[END_REF], ternary logic optical calculator [START_REF] Yi | Design and Experiment of Ternary Logic Optical Processor[END_REF], ternary optical half-adder and full adder [START_REF] Yi | Lane of Parallel Through Carry in Ternary Optical Adder[END_REF] [START_REF] Yi | Lane of Parallel Through Carry in Ternary Optical Adder[END_REF], and tried to develop the corresponding ternary optical computer prototype. But when designing optical calculators in TOC, there is much randomness. Commonly, the designs of optical calculators completely depend on inspiration of designers, so it is possible that different light diagrams are gained by different designers. All these not only make the design of light diagram of optical calculator slow but also make the design quality ensured difficultly; in addition, they also bring the manufacture of the optical calculators on lots of difficulties. These disadvantages are obvious in the development of the ternary logic optical calculators.

In order to solve these problems, a design criterion of multi-valued logic calculator [START_REF] Junyong | Decrease-Radix Design principle for carrying/borrowing free multi-valued calculator and application in Ternary Optical Computer[END_REF] [START_REF] Junyong | Decrease-Radix Design Principle[END_REF] was presented and was applied to the manufacture of ternary logic optical calculators in this paper. According to the criterion, all ternary logic optical calculators can be designed by a few basic units and the calculators have clear structures. It is possible to reconstruct any ternary logic optical calculator with the same basic units group by virtue of the criterion. Followed the design criterion, we have designed and set up a hundreds-bit reconfigurable ternary logic optical calculator in June, 2007. In this paper we introduce the design criterion of multi-valued logic calculator in detail, and also introduce the design, manufacture and the experiment of the hundreds-bit reconfigurable ternary logic optical calculator. [15][16] The operational capability of n-valued logic calculator with two inputs can be defined by the truth table of input and output. This truth table is n×n array in which the element lies in i row and j column is denoted by c ij . And each n-valued calculator must have n different physical states to represent these n values. In order to discuss conveniently, some symbolic definitions are given as follows:

Decrease-Radix Design Rule

(1) Use  i to represent information, and all  i assemble the set i.e. ={ 1 ,  2 , ,  i , ,  n |i=1,2,…,n }.

(2) Use  i to represent physical state, and all  i assemble the set i.e.

={ 1 ,  2 ,,  i , ,  n |i=1,2,…,n }. (3) LT k (n)(k=1,2,…,n) represents a truth
(n) is called the basis-element table BT k (n) (k=1,2,…,n).
Only one element in BT k (n) is not the state D and the other (n×n-1) elements are the state D, then the BT k (n) is a n×n two-value table. Due to there are (n-1) physical states in the set  which are not the state D, there are (n-1) basis-element tables which have one element that is not the state D at the same position; furthermore, there are n×n positions of element in the BT k (n), thus the number of basis-element table is n×n×(n-1) totally.

Select physical states

In principle, the steady physical state which can be transferred from one state to another by apparatus can be used to represent information. Therefore there are many optional schemes of the set , in which those schemes that can generate such set  which contain the state D are the discussion object of this paper, and these schemes can be used to implement multi-valued computer system conveniently.

For example, the wavelength, intensity and polarization direction of light signal can all be used to represent information, in which the no light state is the connatural state D because that when it overlaps with any light signal which have any wavelength, any intensity and any polarization direction, the no light state seems nonentity to the result of the overlap, so it accords with definition 1. If the no light state, vertical polarization light and horizontal polarization light are selected to represent information in one system i.e. = {no light state, vertical polarization light, horizontal polarization light}, there lies the state D (no light state), so the design criterion presented in this paper can be used to complete corresponding design task easily and conveniently. And if only the vertical polarization light and horizontal polarization light are selected to represent information in a system i.e. ={vertical polarization light, horizontal polarization light}, there is not the state D for neither the vertical polarization light fall short of definition 1 nor the horizontal polarization light. This is not the domain of this paper.

Mapping between physical states and information symbols

Commonly, the operational capability of logic calculator is given by the corresponding truth table LT k (n) in which the element is a information symbol, but the implement of it must depend on the physical states transfer. So firstly, the element mapping relationship between physical state set  and information symbol set  must be defined. There are (n!) optional mapping relationships totally, but different mapping relationship corresponds with different complexity of logic calculator structure. In this paper, using the state D to represent the information symbol which is the most frequently appeared in LT k (n), in this way, the final structure of logic calculator is most simple.

Derive from PT k (n)

The truth table PT k (n) can be derived as following steps:

(1) Select an element c ij which value is not the state D from PT k (n).

(2) Construct an n×n array truth table in which all elements are the state D.

(3) Replace the element of n×n array truth table in step (2) which lies in i row and j column with the element c ij in step [START_REF] Yi | Ternary Optical Computer Principle[END_REF]. According to definition 7, this truth table (n×n) replaced is a basis-element table BT k (n).

(4)Repeat step (2) and step (3) for every element c ij in PT k (n) which value is not the state D.

After the above four steps, some different basiselement tables BT k (n) can be derived from the truth table PT k (n), and the number of basis-element table BT k (n) is the same as the number of the element in truth table PT k (n) which value is not the state D. Considering the invariability of physical states overlap with the state D and the rule of matrix addition, the PT k (n) can be obtained by the "addition"of all derived BT k (n). This "addition" is not pure addition operation of mathematical matrix for the base of the "addition" is the invariability of physical states overlap, so it is called DH operation. The another meaning of DH operation is that the PT k (n) can be divided into the seriate DH operation expression of all derived BT k (n).

Definition 3: The device that can realize overlap processing of physical states is called overlapper.

Each truth table corresponds to a calculator, and the calculator corresponding to basis-element table BT k (n) is called basis-element calculator. If overlap the output state of these basis-element calculators using overlapper, then a multiplex calculator can be obtained.

It is obvious that the function truth table of the multiplex calculator is the PT k (n).

A n-valued calculator has n-valued input and output. But because one basis-element calculator has a nvalued input and a two-value output, so the construction of basis-element calculator is simpler than that of n-valued calculator, and it can be realized easily. If the construction of overlapper is simple, then any n-valued logic calculator can be obtained by the combination of several simple basis-element calculators using simple overlapper. This design rule is called Decrease-Radix Design.

Design Criterion of multi-valued logic calculator

According to the above rule of Decrease-Radix Design, the design criterion of n-valued logic calculator is given as follows:

(1) Give the truth table LT k (n) of n-valued logic calculator ready to design.

(2) Select the state D and overlapper.

(3) Using the state D to represent the information symbol which is the most frequently appeared in LT k (n).

(4) Mapping between the other (n-1) physical states and the remainder (n-1) information symbols freely.

(5) Write the truth table PT k (n) corresponding to the LT k (n) using the mapping relationship selected by step (3) and step (4).

(6) Derive from the PT k (n) according to the steps in section 2.3, some BT k (n) will be obtained. [START_REF] Yi | Design and Experiment of Ternary Logic Optical Processor[END_REF] Design the basis-element calculators corresponding with the BT k (n) obtained in step [START_REF] Yi | Lane of Parallel Through Carry in Ternary Optical Adder[END_REF].

(8) Construct the n-valued logic calculator by overlap the output of every basis-element calculator designed in step (7) using overlapper.

Table 1 truth table

LT k (3) of one ternary logic Output c Input a 0 m 1 Input b 0 0 m m m m m m 1 m m 1
For example, the no light state, vertical polarization light and horizontal polarization light (Denoted by W, V and H in the following tables) are selected to represent the ternary information in the system of TOC, and the no light state is the state D. Supposing that the truth table of one ternary logic is shown in Table 1, then the corresponding ternary logic optical calculator can be designed according to the above design criterion, as follows:

Step 1: Write the truth table LT k (3) of the ternary logic, shown in Table 1.

Step 2: The no light state is the state D, and select the half-reflect and half-transmission mirror as the overlapper.

Step 3: Use the no light state (state D) to represent m which is the most frequently appeared in Table 1.

Step 4: Use the horizontal polarization light (H) to represent 0 and vertical polarization light (V) to represent 1.

Step 5: Write the truth table PT k (3) corresponding to the LT k [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF], shown in Table 2.

Table 2 PT k ( 3)

Output c Input a W V H Input b W W W W V W V W H W W H
Step 6: Derive from the PT k (3) according to the steps in section 2.3, as follows:

(1) Select the element c 22 =V from Table 2.

(2) Construct a truth table (shown in Table 3) in which all elements are W (the state D).

Table 3 truth table (3×3 ) Output c Input a W V H Input b W W W W V W W W H W W W
(3) The basis-element table BT m (3)(shown in Table 4) is derived by replace the corresponding element of Table 3 with the element c 22 selected in step [START_REF] Yi | Ternary Optical Computer Principle[END_REF]. As the input a1 and b1 in Table 4 are the beam splitting from the input optical path a and b in Table 3 respectively, so a1=a, b1=b.

Table 4 BT m (3)

Output c1 Input a1 W V H Input b1 W W W W V W V W H W W W (4) Select the element c 33 = H from Table 2.
(5) Construct a truth table (shown in Table 3) in which all elements are W (the state D).

(6) The basis-element table BT n (3)(shown in Table 5) is derived by replace the corresponding element of Table 3 with the element c 33 selected in step (4). As the input a2 and b2 in Table 4 are the beam splitting from the input optical path a and b in Table 3 respectively, so a2=a, b2=b.

Table 5 BT n (3)

Output c2 Input a2 W V H Input b2 W W W W V W W W H W W H
Step 7: Design basis-element calculators (shown in Figure 1 and Figure 2) corresponding with the BT m [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF] and BT n (3) respectively. In Figure 1 and Figure 2, a1,a2,b1 and b2 are the input optical path, c1 and c2 are the output optical path, v1,v2 and v3 are the polarizer that only permit vertical polarization light pass(Denoted by vertical polarizer in following part), h1,h2 and h3 are the polarizer that only permit horizontal polarization light pass(Denoted by horizontal polarizer in following part), LC1 and LC2 represent the liquid crystal unit which disable the optical rotation when the input optical path of light controller is not the no light state, the broken line represents the input optical path of light controller. The working principle of Figure 1 is: a closed light valve consists of v2, v3 and LC1, when input a1 is the horizontal polarization light or no light state, no light can pass through v1, the LC1 rotates light, then the valve closed and output c1 is no light state whatever the input b1 is. When the input a1 is the vertical polarization light which can pass v1 and LC1 disable optical rotation, then the light valve can let the vertical polarization light pass. At the same time, if the input b1 is also the vertical polarization light, then it can pass through light valve to output c1, so c1 outputs the vertical polarization light. If the input b1 is not the vertical polarization light, for b1 cannot pass through light valve, c1 outputs the no light state. The conclusion can be obtained here that it is only when a1 and b1 are the vertical polarization light at the same time c1 can output the vertical polarization light, otherwise c1 outputs the no light state. So light diagram in Figure 1 realizes the BT m [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF]. The workong principle of Figure 2 is similar to that of Figure 1, only when a2 and b2 are the horizontal polarization light at the same time, c2 can output the horizontal polarization light, otherwise the no light state. That is, light diagram in Figure 2 realizes the BT n [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF].

Step 8: The final structure of this ternary logic optical calculator shown in Figure 3 is the result of overlapping the outputs of c1 in Figure 1 andc2 in Figure 2 into one output light path c using the overlapper f(here is the half-reflect and halftransmission mirror). The symbols in Figure 3 are the same as those in Figure 1 To any ternary logic, so long as there is the corresponding truth table, the corresponding normative ternary logic optical calculator can be designed step by step according to the above method.

Implementation of hundreds-bit reconfigurable ternary logic optical calculator

Carrying out ternary logic operation directly is one of the characters of the tenary optical computer. And ternary optical half-adder, ternary optical full adder, ternary optical multiplier and other important components are all based on ternary logic operation. So the implementaion of a well-designed ternary logic optical calculator is the precondition of the ternary optical computer prototype, and its capability and bulk determine the future ternary optical computer's capability and bulk directly.

The advantage of above design criterion is using comparatively simple basis-element calculators to "assemble" various logic calculators. This character make the reconfiguration on the hardware of the ternary logic optical calculator is possible. A hundreds-bit reconfigurable ternary logic optical calculator is implemented using the apparatus which is current in market, such as liquid crystal display, polarizer, embeded system etc. and VC etc. developing eviroments in this paper. The following introduces the design, manufacture and the experiment of this reconfigurable calculator in detail.

Design of basis-element calculator

According to definition 2, it can be concluded that there are 3×3×(3-1)=18 basis-element tables BT k [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF] in ternary logic optical calculator. These BT k [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF] and corresponding basis-element calculators A k (3) (k=1,2,…,n) designed are shown in Table 6. 4 18 Table 8 Figure 5 The basis-element table lies in No. 17 of Table 6, has an element which value is the vertical polarization light when two inputs are no light state. The corresponding calculator can not be realized by liquid crystal unit without lamp-houses. A method is presented to resolve the difficulty in this paper, as follows: change the physical states of inputs, that is, replace the no light state with the horizontal polarization light, and replace the horizontal polarization light with the no light state. The working principle of Figure 4 is similar to that of Figure 1, only when two inputs, a and b, are the no light state at the same time, and change to the horizontal polarization light, then c outputs the vertical polarization light, otherwise the no light state. Light diagram in Figure 4 with the above state changing method realizes the BT 17 [START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF]

W V W W V W W W H W W W
Changing the physical stats of inputs means the encoding method on the two basis-element calculator is different with the others. Because the calculator and the corresponding encoder are determined before the beginning of data processing, the actual operation of encoder is choosing a corresponding coding method on these optical paths which are inputs of the two basiselement calculator. This will not add anything to the complexity of encoder. So this method is viable.

Table 8 BT 18 (3)

Output c Input a W V H Input b W H W W V W W W H W W W

Design and manufacture of the hardware part

Analyzing the structure of light diagrams of the eighteen basis-element calculators in Table 6, the representative structure can be abstracted (shown in Figure 6), as follows:

(1) There are two beam splittings: one is the main optical path y, the other is the control optical path x which disable or enable the optical rotation of liquid crystal unit LC.

(2) There is a liquid crystal unit LC in the main optical path y, the front and back sides of which has a polarizer respectively: P1 and P2.

(3) The liquid crystal unit LC is light controlled.

Nowadays, the technology of light controlled liquid crystal [START_REF] Khoo | Self-phase modulation and optical limiting of a low-power CO2 laser with a nematic liquid-crystal film[END_REF][13] [START_REF] Janossy | Molecular interpretation of the absorptioninduced optical reorientation of nematic liquid crystals[END_REF] is matured in the laboratory. But considering the process of TOC's research at present and the market of light modulator, at the condition that the principle can be validated by experiment, the selection of apparatuses needed abides by the principle that is the least spending of time and money. So the electronic controlled liquid crystal unit which is current in market is selected to replace the light controlled liquid crysta unit LC. Correspondingly, the optical controller is replaced with the electric controller, and Figure 6 is changed to Figure 7. The defect of this design is the low efficiency of the optical-electricoptical control used to realize the optical-optical control indirectly. For this detect will not effect the aim of the design and experiment, considering the advantages and the corresponding disadvantages, we choose this design.

For the function of optical controller in Figure 6 is realized by the function simulation of electric controller in Figure 7, the optical hardware of this system is only the main optical path y.

The electric controller in Figure 7 has an input which is ternary signals (the no light state, vertical polarization light and horizontal polarization light), and an out which is binary signals. The output signals are used to disable or enable the optical rotation of liquid crystal unit LC. In this paper, the symbol 0 represents the output signal which disables the optical rotation of LC, and the symbol 1 represents the output signal which enables the optical rotation of LC. The electric controller can realize 2 3 =8 control logics, the corresponding truth table is C 1 , C 2 … C7 and C 8 , as shown in Table 9.

Table 9 8 truth tables of electric control logic Output Symbols of control logic

W 0 0 0 0 1 1 1 1 V 0 0 1 1 0 0 1 1 H 0 1 0 1 0 1 0 1
There are two kinds of polarizer on the both sides of liquid crystal unit LC in the main optical path y: vertical polarizer and horizontal polarizer. Thus, the 10. Then, according to Table 6, Table 9 and Table 10, the type name of hardware unit and the symbol of control logic which the eighteen basis-element calculators A k (3) of ternary logic optical calculator belongs to, can be listed in Table 11.

Table 11 Hardware unit types and electric control logic of A k (3)

A k (3)
Types name of hardware unit

Control logic name of electric controller

A 1 (3) V-V C 4 A 2 (3) V-V C 4 A 3 (3) V-H C 5 A 4 (3) V-H C 5 A 5 (3) H-V C 5 A 6 (3) H-V C 5 A 7 (3) H-H C 4 A 8 (3) H-H C 4 A 9 (3) V-V C 6 A 10 (3) V-H C 3 A 11 (3) H-V C 3 A 12 (3) H-V C 3 A 13 (3) V-H C 2 A 14 (3) V-H C 2 A 15 (3) H-V C 2 A 16 (3) H-H C 7 A 17 (3) H-V C 2 A 18 (3) V-H C 3
According to Figure 8 in which black areas represent the vertical polarizer, gray areas represent the horizontal polarizer and the white gridding middle area represents liquid crystal, adding corresponding polarizers on two faces of a electronic controlled liquid crystal display array(type: YMSG-G12864P-12DYSWSN), then there are four separate areas in the liquid crystal array: area V-V, area V-H, area H-H and area H-V from left to right (shown in Figure 8). For the liquid crystal array has 64×128=8192 pixels, and each pixel can be used as one optical path, then there are 64×128=8192 optical paths totally and 64×128/4 = 2048 optical paths in each area. Considering the function stability of real system, it is necessary to use several pixels to represent one optical path redundantly. It is use 2×2=4 pixels as one optical path in this system, so there are 64×128/16=512 optical paths in each area, correspondingly the maximum data bits of the reconfigurable ternary logic optical calculator is 512 too. Thus the hardware part of the reconfigurable ternary logic optical calculator is completed, and the practicality photo is shown in Figure 1 of appendix 2. The system circuitry board made by ourselves is shown in Figure 2 of appendix 2, which supplies the hardware interface between liquid crystal module and embedded control chips, and realizes eight control logics in Table 9.

Architectures of experiment system

The whole architectures of experiment system is shown in Fighre 9, wherer R represents surface lamphouse, C represents coder, P represents the hundredsbit reconfigurable ternary logic optical calculator completed in section 4.2, D represents decoder, L represents homogenized beam of light, and S represents data stream.

The coder C realizes the data stream S represented with light state by modulating from homogenized beam of light L to ternary information beams. The working principle of C was introduced in Reference 11. The decoder D is a light-electron conversion device which can convert the ternary light information to binary electronic information.

The software of this system includes two parts: position machine and embedded part. The two parts

Process and result of experiment

There is a software module in this system, which can realize the simulation display and analysis of current experiment results. So users can find errors visually in the operation interfaces directly, and the process of experiment is convenient and instant.

This system has carried out almost thousands of ternary logic operation during several months. The range of data bits used in operations is from severa to hundreds. The system is steady and reliable, and the operation results are acoup sur, which correspond with the expectant results totally. It can be concluded that the design criterion of multi-valuedlogic calculator presented in this paper is validity and efficient.

At present, this hundreds-bit reconfigurable ternary logic optical calculator has become a special demo system for visited and investigated. In this demo system, visitors can define any ternary logic freely, and the result of logic operation can be seen with either decoder or naked eyes when inputting any two hundreds-bit datum. Welcome anyone anytime visits the department of Computer, Shanghai University to investigate this system. The simpleness and efficiency of this system can make you surprised.

Conclusions

In this paper we present the design criterion of multi-valued logic calculators. The advantages of the design criterion are that any logic calculator can be formed with a few basic units which have simple structures. We have applied this method to the design of the ternary logic optical calculator and have set up a hundreds-bit reconfigurable ternary logic optical calculator successfully. All these promote an investigation on the key parts and the development of the Ternary Optical computer.

Figure 2

 2 Figure 1 Basic operation unit corresponding to BT m (3)

Figure 4 Figure 3

 43 Figure4A 17[START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF] corresponding to BT 17[START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF]

  Figure5A 18[START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF] corresponding to BT 18[START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF]

Figure 8

 8 Figure 8 Allocation of polarizator

  table of nvalued logic, in which all the elements c ij belong to the set . It is possible that there is no the state D in the set , but it is also possible that there are several states D in the set .

[START_REF] Yi | Lane of Parallel Through Carry in Ternary Optical Adder[END_REF]

PT k (n) (k=1,2,…,n) represents a truth table of nvalued logic, in which all the elements c ij belong to the set . Definition 1: If the result is still  i when one physical state in set  overlaps with  i (∈), the physical state is called the state D. Definition 2: If only one element in the truth table PT k (n) is not the state D, then this truth table PT k

Table 6 18

 6 BT k[START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF] and 18 A k[START_REF] Yi | Ternary Optical Computer Principle and Architecture[END_REF]

	No.	BT k (3)	A k (3)
	1	Table 1 in Appendix 1	Figure 1 in Appendix 1
	2	Table 2 in Appendix 1	Figure 2 in Appendix 1
	3	Table 3 in Appendix 1	Figure 3 in Appendix 1
	4	Table 4 in Appendix 1	Figure 4 in Appendix 1
	5	Table 5 in Appendix 1	Figure 5 in Appendix 1
	6	Table 6 in Appendix 1	Figure 6 in Appendix 1
	7	Table 7 in Appendix 1	Figure 7 in Appendix 1
	8	Table 8 in Appendix 1	Figure 8 in Appendix 1
	9	Table 9 in Appendix 1	Figure 9 in Appendix 1
	10	Table 10 in Appendix 1	Figure 10 in Appendix 1
	11	Table 11 in Appendix 1	Figure 11 in Appendix 1
	12	Table 12 in Appendix 1	Figure 12 in Appendix 1
	13	Table 13 in Appendix 1	Figure 13 in Appendix 1
	14	Table 14 in Appendix 1	Figure 14 in Appendix 1
	15	Table 15 in Appendix 1	Figure 15 in Appendix 1
	16	Table 16 in Appendix 1	Figure 16 in Appendix 1
	17

Table 7 Figure

 7

  in Table 7. The basis-element table lies in No. 18 of Table 6 is similar to the above, it only need to replace the no light state with the vertical polarization light, and replace the vertical polarization light with the no light state. Table 7 BT 17

Table 10

 10

		Types of optical hardware unit
	Types Name	P1	P2
	V-V	vertical polarizer	vertical polarizer
	V-H	vertical polarizer	horizontal polarizer
	H-H	horizontal polarizer horizontal polarizer
	H-V	horizontal polarizer	vertical polarizer

 Supported by the Science and technology projects of Jiangxi Provincial Education Department (Grant No.GJJ09560) and the Youth Foundation of Jiangxi University of Finance and Economics (2008)

Appendix 1 16 basis-element tables BT k (3) and corresponding basis-element calculators A k (3) in ternary logic optical calculators

In the following figures and tables, a and b are the input optical path, c is the output optical path, v1,v2 and v3 are the polarizer that only permit vertical polarization light pass, h1,h2 and h3 are the polarizer that only permit horizontal polarization light pass, LC represents the liquid crystal unit which disable the optical rotation when the input optical path of light controller is the no light state, RLC represents the liquid crystal unit which disable the optical rotation when the input optical path of light controller is not the no light state, the broken line represents the input optical path of light controller, W is the no light state, V is the vertical polarization light, and H is the horizontal polarization light. The working principle of following figures is similar to that of figure 1 of the text.

Appendix 2 Photos of hardware practicalities and software interface


Haijiang Tai

Qisheng Ding

Daoliang Li

Yaoguang Wei

Design of an Intelligent PH Sensor for Aquaculture Industry

Keywords:

Abstract

Introduction

Over the past decade, the development and applications of chemical sensors and biosensors have grown rapidly. Among all sensors, pH sensors have received the most attention because of the importance of pH measurement in various scientific research and practical applications. China's water quality online automatic monitoring technology is laggard; a lot of monitoring methods are still traditional, testing data lags behind seriously. Monitoring instrument water quality auto-monitoring system mainly use 2-wire transducers, exist amount of problem, such as poor stability of signal, high cost, single function, can't connect with field bus control system(Xu hao, 2007).

Intelligent of water quality monitoring instrument is important to improve the level and production mode of aquiculture, as a result, amount of intelligent monitoring instruments were developed, more perfectly water quality monitoring instrument were sold by America, Japan, Italy, and so on (Fan Xiang-guo, 2005); at present, In this paper, an intelligent PH sensor was developed according to IEEE145 standard, read sensor data and set actuator parameter by using Transducers Electronic Data Sheets (TEDS) so as to achieved "Plug and play" function [START_REF] Miroslav | Integrated Smart Sensor Networking Framework for Sensor-based Appliances[END_REF]. Water temperature and pH can be measured on-line by the intelligent pH sensor. Conversion of the current and amplification of the voltage is achieved by using three high impedance, low drift operational amplifiers TLC27L4; two of them make up differential amplifier, and its input resistance up to 3×1012ohm, to ensure the input signal not affected by resistance change. Moreover, differential circuit have high CMRR, can adapt to complex Industry-environment.

Hardware of the sensor

In order to meet the market demand, and meet the requirement of remote transmission and networking, the sensor uses RS-485 field bus to make connection and achieve the communication between CPU and Remote I/O by using a SN75LBC184 RS-232/RS-485 convertor. Two resistors (20ohm in this work), R1 and R5, were series connected to the output terminal of SN75LBC184, avoid network failures of a single hardware device affect network. The electric circuit used to drive the sensor and to treat the signal is shown in Fig. 2.

Experiment

The sensor probe used in this work is based on composite glass electrode HG990 manufactured by Shanghai leici instrument Inc.

The effect caused by temperature was measured by using PH standard buffer solutions at pH 4.00, 7.00 and 9.00 manufactured by American HACH Company under the range of 0~40℃.

Calibration experiment did by using PH standard buffer solutions at pH 4.00, 6.93 and 9.41 manufactured by American HACH Company. Experiments were carried out at room temperature, and the measured temperature of standard buffer solution at (26.7±0.1)℃.Six measurements at 5min intervals were recorded for each standard solution to test reproducibility of the sensor probe by immersing the probe in the solution and lasts 5 min, and then took the probe out after the sensor put out stable signal.

Results and discussion

Fig. 5 shows the results of temperature effect. As can be seen, no significant temperature effect in the three PH standard buffer solutions.

Conclusion

The intelligent PH sensor based on IEEE1451standard combined traditional sensor, microcontroller and TEDS technology, thus, the sensor was more intelligent. Concrete representations as following:

(1) Transmit data by applying all-digital bus, easy to apply in monitoring network;

(2) Intelligent sensor interface module based on IEEE1451 standard achieved plug and play functionality;

(3) Simplified the hardware structures by combining MCU and electrochemistry test technology, expanded measurement function, reduced the cost, improved reliability and measurement precision;

(4) Achieved low power consumption by using low power cost MCU (msp430).

  water quality monitoring instrument have rapid development in China, various PH monitoring instruments developed by Tsinghua University (Fu Xiao-shi et al., 2004; Gong Yuan-ming et al., 2003), Southeast University (Chen Ming-wei et al., 2005), Jiangsu University (Liu Xing-qiao et al., 2006), and so on. The above water quality PH monitoring instrument bases on MCU generally, monitor single or multiple water quality parameters, achieved electrode calibration and Temperature compensation by using software, but it is difficult to connect with field bus control system (Yang Su-ying et al., 2004). Some instruments can connect with field bus control system, but the problem of the interface and incompatibility are generally exist between multi-sensor and actuator (L.Camara, 2004; Institute of Electrical, 1997; Guangming Song et al., 2005; Antonio Pardo, 2006).

2. 1

 1 Hardware structureThe sensor mainly contained signal conditioning model, A/D circuit, power source model, microprocessor and Transducers Electronic Data Sheets (TEDS), Hardware structure of the pH sensor is shown in Fig.1

Fig. 1 .

 1 Fig. 1. Hardware structure of pH sensor

Fig. 2 .Fig. 3 .Tab. 1 . 3 . 3 Fig. 4 .

 231334 Fig. 2. Electric circuit for the sensor signal treatment

Fig. 5 .Fig. 6 .

 56 Fig. 5. Temperature effect of an intelligent pH sensor

Acknowledgements. This work was supported by 863 programs "Research and Application of Digital Integrated System for Intensive Aquaculture" (2007AA10Z238), 948 Project of China Agriculture Ministry (2010-Z13). And the programs "Development and Applications of sensor network applied to monitor bloom of blue-green algae in Taihu Lake" (2010ZX03006-006)


Fang Wang

Qingling Duan

Lingzi Zhang

Guo Li

Modeling and Analysis of Pollution-Free Agricultural Regulatory Based on Petri-Net

Keywords: workflow, pollution-free agricultural products, Petri net, work flow model, equivalent simplification, model performance

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

 Pollution-free agricultural products is the production that area, production process and product quality meet the national requirements of the relevant standards, Obtain a certificate and allow use the sign of pollution-free agricultural products [START_REF] Maaiguo | Fuxueliu . Pollution-free agricultural management and technology Beijing[END_REF]. Currently, the pollution-free agricultural products certification used in turn by the county, Agency-level work, provincial, sub-centers, the center of Ministry, and all other working bodies for approval step by step. But the information and instruments which  * Corresponding author, Email: dqling@cau.edu.cn used during the Certification at all levels of agency transfer by Postal service. This manual method is not only cost a lot of manpower, financial resources but also time.

And can not do government affairs. Therefore, the design and development of electronic control systems is the trend of pollution-free agricultural products. One of the key technologies to achieve the system is how to achieve pollution-free agricultural systems certification information automatable transfer during at all level of work agencies. The workflow technology leaded into the PFARS can solve the problems. Workflow technology according to the system real operational rules can make certified information fully or partially run automatically, in order to make the documents, information or tasks in business processing can automatic transfer and implement [START_REF]Wangguangwei.Workflow-based e-government system and implementation of[END_REF].

Model is the most important elements to determine the quality of workflow system.

In this paper, we use the Petri Net which has a strict mathematical basis for pollution-free agricultural products regulation system workflow model to described certification business behavior, and an improved model method to verify the performance of the model.

Pollution-free agricultural regulatory system modeling

Petri net technology and work flow model

Petri net invented by Carl • A • Petri in the 1960s [START_REF]Yuanchongyi.Petri Net Theory and Applications[END_REF], is a parallel system of discrete mathematics, suitable for describing asynchronous, concurrent computer system model. Petri nets can be graphically described the workflow, and own standard, clear and rich analysis techniques, to avoid ambiguity, uncertainty and contradiction. This method is one of the most common methods to construct the workflow model.

Petri net is a two-way map that consisted by Place, Transition and the relation between them. Definition 1: A Petri net is a necessary and sufficient conditions to satisfy the following triple N = (P, T, F) [3] . The structure of a Petri net elements include: place, transition and the arc. Place used to describe the possible local state (condition or status). Transition describes the events which modified state of the system. Arc is the relationship between place and transitions.

Workflow model is the basis for workflow management systems. Workflow model the abstract and refine of the actual business processes, is the idea of workflow and workflow terms of the business process description and modeling results [START_REF]Jiangchangjun.The behavior of Petri net theory and its applications Beijing[END_REF].

Workflow model includes all information which can execute by workflow engine, the information contains the condition to start or end a business process, the flow relation of the control data, Participants, organization, data, the application may be invoked, and all definition data which relevant to workflow. Workflow model consisted by two basic elements there are nodes and connecting, which is defined as a directed graph

{ , } W N L 

, N is the node set, L is the set of arc connections between nodes. In workflow model node stands for all activities, which refers to the general work unit. Each activity is independence and has its own properties.

Examples of activities are task, for different process instance, the same activities may have different tasks.

In the design of pollution-free agricultural products certification business workflow model is not only to describe the workflow process model, but also describe the certification body of the organization model, resource model, and provide information related to the definition of workflow data to make it a complete, multi-view of the model [START_REF] Van Der Aalst W M Hee K Mmvan Der Toom | Component-based software architectures:a framework based on inheritance of behavion BETA Working Paper Series[END_REF].

The pollution-free agricultural products certification net model

In system, organizational model consists of five elements: "staff", "role", "post", "department" and "working group. (2) Department: is set for functions. In general, department is a agency which has the same location, goal and task. In addition to personnel other than, the other entities in system is a sub-level tree structure layer by layer.

( that do not pass a formal examination, T3 that do not fill in the form of review of information through the comments, T4 confirmed that compliance approval, T5 that approval be returned to confirm compliance, T6 that fill approval to return to confirm the views of compliance information, T7, said approval to appoint inspectors, T8, said approval to appoint inspectors to return processing, T9 complete approval to appoint inspectors to return views of information, T10, said a comprehensive inspection approval, T11 comprehensive examination that approval be returned, T12 that a comprehensive examination of information processing views of complete return, T13

found that approval of origin, T14 found that approval of origin return processing, T15 found that approval of origin information filled returned opinions, T16 preliminary approval of products, T17 preliminary approval that products be returned, T18 Product preliminary approval, said approval of the views of complete return information, T19 review for approval of products, T20 review for approval of products be returned, T21 complete return of products to review for approval the views of information processing, T22 that generate batch processing, T23 that approval be returned batch generation , T24 fill in return for approval, said approval of the batch generation views information, T25 Final review of products, T26 Final review that product be returned, T27 Final return products that fill in the information processing view, T28 review that certificate number generated by, T29 reported that approval document signed audit through.

Model Performance Analysis

Traditional network based on Petri workflow process model built performance analysis method has exponential time complexity, based on pollution-free agricultural products certification process certified business link in task completion time of uncertainty, assumptions in the certification process to prepare an adequate prerequisite for certification material condition cases, pollution-free agricultural products certification based on drift-nets, stochastic Petri net equivalent simplification approach can introduce random trigger Petri-Net, we propose a linear time complexity of the average running time of workflow approximate performance analysis method, to make the capabilities of the model more precise analysis of time performance .

In the continuous-time stochastic Petri net, a change can be implemented from time t to the implementation of the delay between the time seen as a continuous random variable, subject to A as a parameter of exponential distribution. A t is the average implementation rate of change that can be implemented in the case of the implementation unit of time the average number. The reciprocal of the average implementation rate of 1/2 as changes t 0, is the average implementation delay or average service time.

Combined with pollution-free agricultural products certification nets in the certification business for the execution time of the exponential distribution, the model of relief activities T i , where (1 ≤ i ≤ n) associated with a rise rate t  , which t  is greater than 0, the real parameter, and A certified business for T to become enabled from time to time between it being raised as a continuous random variable X i (to take a positive real number), and subject to a distribution function

( ) { } tt F x X x  ,
the n random variables X i (1 ≤ i ≤ n) as independent random variables. The distribution function can be defined as an exponential distribution function:

( ) 1 ( )

x t F x e t T      
that the random variable X t parameters obey the

 1
).

According to the actual certification of pollution combined with expert opinion, statistics Figure 8 the various certification business for the time

Conclusion

This paper proposes a method to construct the first pollution-free agricultural products certification through use of Petri-net by analysis the actual requirements of the pollution-free agricultural regulatory operations and study the techniques of the workflow modeling. The model can clearly describe the certification business processes, lay a good foundation for the stable operation of the system. Moreover, to prove the performance of the workflow model, proposed the model reduction and stochastic Petri nets combination of authentication methods. By study the model verify that it is applied to the feasibility of pollution-free agricultural regulatory system can improve efficiency, government affairs, information sharing.

The system is currently in trial operation phase, the performance is steady; apply to the country of five pollution-free agricultural regulatory agencies to jointly monitor the actual business process management needs.

( 1 )

 1 PT    (Net of non empty); (2) PT    (Duality)Not isolated elements). Where dom(F), cod(F), respectively on behalf of the domain and range.

Figure 1

 1 Figure 1 Certified pollution control system model diagram

Figure 2

 2 Figure 2 Organization Model Entity Relationship Diagram

Figure 3 1 )Fi gure 4

 314 Figure 3 System of work organization

( 2 )Figure 5 ( 3 )Figure 6 Figure 7

 25367 Figure 5 Role model professional certification sub-centers

  equivalent Petri Net reduction rules, pollution-free certification model simplified model shown in Figure 8:

  review by the time the work of institution-level audit time workflow process model, mainly composed by the sequence structure. Change t1, t3, t5, t7, t9, t11, t13, t15, t17, t19, constitute the order structure

(

1

 1

    ). Change t1 which constitute part of county-level certification; change t3, t5, t7, constitute part of prefecture-level certification; change t9, t11, constitute part of the provincial certification; changes t13 certification form part of sub-centers; changes t15, t17, t19, constitute the Department of Center Certification link; know that normally the average processing time is: 405m, largely for the certification of agricultural products now save time and money.

  " The relationship of the Organizational model shown in Figure2:

	Department Role	Composition Qualifications	Staff Set up Set up	Responsible for Set up	Working Group Post	Function-oriented Business process-oriented


Xiaoling Luo
email: xiaolingluo@126.com

Lei Deng

Nondestructive Testing Technology and Optimization of On-service Urea Reactor

Keywords: Urea reactor, Defect, Nondestructive testing, Optimization

The paper analyses possible types, shapes and locations of defects in a life cycle according to such factors of a urea reactor as material, structure, manufacture approach, work environment, operating medium and failure mode. Then suitable nondestructive testing methods are chosen to test a urea reactor on service on the basis of characteristics of various nondestructive testing methods. And test procedures are optimized which not only ensure urea reactor safety operation, but also reduce test time and minimize plant stand-by loss caused by a test.

Introduction

A urea reactor is a key equipment in a urea production, it works under high temperature, high pressure and strong corrosion which may bring about defects such as stress corrosion crack and fatigue crack, and even worse, it may cause accidents such as cylinder crack, leakage, or even explosion [START_REF] Lin | Nondestructive Testing Techniques for Pressure Vessels[END_REF] . Therefore, even if a urea reactor design, manufacture and installation quality totally meets all codes and standards, there can still be some potential safety hazards when process run for a period. It will bring about accidents if not eliminate the failures timely, the common practice to insure urea reactors safe operation is to have a complete detection and mending at regular intervals besides real-time monitor.

Urea reactor operating conditions and characteristics

Urea reactor operating conditions and characteristics

Operating pressure ≤ 22MPa; Operating temperature ≤ 200℃; Working medium: liquid ammonia, CO 2 and methylamine, etc.

Working characteristics

High temperature, high pressure and strong corrosion.

Structural characteristics

Most on-service urea reactors are weld-shrunk multilayered cylinder consisting of liner layer, blankoff plate layer, inner cylinder and layer plate [START_REF] Ding | The urea synthesizes the tower's corrosion and counterplan[END_REF] . A urea reactor cylinder has 14 layers with a total thickness of 110mm. Generally liner material is 316L stainless steel with 8mm thickness and blankoff plate material is Q235-A carbon steel with 6mm thickness and inner cylinder material is 16MnR low alloy steel plate with 12mm thickness and layer plate material is 15MnVR with 6 to 8mm thickness.

Urea reactor regular defect

Manufacture defects

There is merely design defect of urea reactor because it is a high pressure vessel and design organizations must have pressure vessel design permission, besides, weld-shrunk multilayered cylinder technology is a proven technique. Defects are mainly caused by a slipshod manufacture process.

Manufacturing defects are as follows [START_REF] Shi | Non-destructive Inspection Technology in Urea Converter Periodic Inspection Application[END_REF] :

(1) That unreasonable structure and discontinuous shape size are easy to result in problems such as stress concentration. (2) Defects such as cracks inside weld joints, incomplete fusions, incomplete penetrations, slag inclusions and gas cavities, etc. (3) Defects such as cracks outside weld joints, incomplete fusions and undercuts, etc. (4) Defect that bead weld layers don't joint with base materials. (5) Reheat cracks under bead weld layers.

Application defects

Affected by factors such as inside medium, outside ambient medium, leak detection medium, compressive load and temperature load, urea reactor working environment is severe bad, as a result, defects are brought about as follows:

(1) Liner and weld bead corrosion thickness decrease, intercrystalline corrosion, selective corrosion, stress corrosion, crevice corrosion, pitting corrosion and cracks may be accompanied with corrosions mentioned above caused by methylamine.

(2) Veneer sheet and weld bead corrosion crack caused by methylamine. (3) Veneer sheet and weld bead stress corrosion cracking caused by outside ambient medium and leak detection medium. (4) Fastener cracks.

(5) Cracks in discontinuous shape size surface caused by stress concentration.

NDT Application in a Urea reactor periodic inspection

Nondestructive Testing (NDT) detects various materials, components and structures subsurface and external defects, making a judgment and evaluation on defect type, quality, quantity, shape, location, size, distribution and changes according to textural anomaly insides material or changes of heat, sound, electricity and magnetism caused by defects, without damaging the equipment [START_REF] Wang | General Knowledge of Non-destructive Inspection[END_REF] .

Penetrant Testing

Penetrant Testing (PT) is one of the earliest nondestructive testing methods and based on capillarity to reveal open defects on a non-porous material surface. Infiltrate the penetrant into open defects on a workpiece surface, remove the surplus penetrant, and then show defects with the help of developer.

Main detect positions and requirements PT is in a urea reactor are as follows:

(1) 100% PT on a lining layer soldered joint surfaces.

(2) 100% PT on girth joint capping plate corner joint surfaces and connector capping plate corner joint surfaces.

(3) 100% PT on joint surfaces between an adapter tube and a weld overlay, an adapter tube and a lining layer as well as internal parts and a lining layer. (4) 100% PT on joint surfaces between an adapter tube and an end plate, an adapter tube and a main body, an adapter tube and an adapter tube. (5) A random PT on a weld overlay focus on appearances where may have problems. Penetrant Testing is accepted according to JB/T 4730-2005 first class, and any surface blowhole is not allowed.

Magnetic Particle Testing

Magnetic Particle Testing (MT) is a kind of NDT which shows defects on the surface of ferro-magnetic material and composition metal based on interaction of magnetic leakage field and magnetic power. MT is widely used to detect cracks, crease, interlining and cinder inclusion on or near ferro-magnetic material surfaces.

Main detects position and requirements are as follows:

(1) 100% MT on an external surface of a circular joint between a cylinder and an upper or a lower head. (2) No less than 50% MT on a cylindrical shell section longitudinal seam external surface and girth joint between sections. (3) Random inspection on veneer sheets, focus on appearances where may have problems. (4) Kingbolts should be cleaned one by one, damage and cracks should be checked, MT should be done when necessary. Bolt that there are circular cracks on thread and transition section should be replaced. MT is accepted according to JB/T 4730-2005 first class.

Ultrasonic Testing

Supersonic wave attenuates when travels through a medium, and is reflected back when comes to a interface. This is exactly the principle Ultrasonic Testing (UT) used to detects defects. UT has many advantages, such as high sensitivity, good directive property, good penetrability and fast. UT is widely used in urea reactor test because of an ultrasonic flaw detector has small cubage, light weight, conveniently portable and operate and harmless compared with ray.

Main detects position and requirements are as follows:

(

Radiographic Testing

Radiographic Testing (RT) is a kind of NDT which is based on the difference absorptivity of ray breakthrough testing workpiece (no matter electromagnetic radiation or particle radiation) to show defects inside a workpiece. Main RT used in industry is X-ray, γ-ray and neutron-ray, besides, X-ray is the most widely used.

Deep girth joint RT can be taken when there are questions after UT or an inspector considers necessary.

RT is accepted according to JB/T 4730-2005 second class.

Acoustic Emission Testing

Acoustic Emission (AE) is a physical phenomenon which refers to that once an object suffers shape change or external affection, it will soon releases elastic energy and then generates stress wave. Acoustic Emission Testing (AET) is one of the methods that work through detection device to analysis acoustic emission signal and detect defects by the signal [START_REF]Acoustic emission examination and evaluation of metallic pressure vessels[END_REF] .

AET should be taken after agreement from testing unit and end user, AET is accepted following the standard which is made beforehand.

Detect scheme optimization exploring

Visual testing (VT) is a simplest urea reactor test method, which detects through sight, hear and tactile organs and experiences. It needs other non-destructive testing technologies as supplementary sometimes because VT can only be used in detecting external defects which can be distinguished by a sense organ. MT is used to test a surface and near a surface flaw and has a low requirement of surface finish quality, high defect discovery rate, high flaw detection reliability, low cost and fast working speed. However, it can only be used for a pressure vessel made of ferro-magnetic material. PT is used to test surface split defects and has a high surface finish quality requirement, and flaw detection sensitivity is strongly influenced by defect breadth-depth ratio, defect types and operating correct or not, therefore PT is usually used in case where MT cannot work (such as fillet weld). RT is more sensitive to capacity defects rather than to some small cracks, especially those crack defects with a transillumination angle of more than 30 degrees. Nowadays RT is considered to be the most suitable Non-Destructive Testing Technology for harmless defects test, but it is of heavy defect detection workload, cost more, and it is harmful to health. UT is of high sensitivity and able to detect extremely harmful planar defects. A lightweight equipment is easy to be operated, so it can make a fast test with a low cost, what's more, it is harmless to health. But there are certain difficulties about defect qualitative and quantitative; therefore it calls for carefulness and experience.

Altogether, optimization non-destructive testing order based on a dangerous defect is VT, MT, PT,UT and RT, according to various non-destructive test applicable occasions and features as well as the theory that a surface defect is much more dangerous than a latent defect.

Conclusion

In recent years, Non-Destructive Testing Technology has developed rapidly, and some new testing methods have been brought into use, such as metal magnetic memory test, infrared thermography testing, ultrasonic phased array inspection, laser-based non-destructive testing, etc. Non-Destructive Testing Technology has been extensively involved in the development of national economy, and will get faster development and be more widely used in the future.


Ying Qiu
email: qiuying72@163.com

Detecting and Analyzing System for the Vibration Comfort of Car Seats Based on LabVIEW

Keywords:

In this research, LabVIEW 8.5 is taken as the software platform. Sensors, data acquisition cards are combined as its hardware. A detecting and analyzing system for the vibration comfort of car seats is developed, in which the functions as to the collecting and processing of vibrating signals, the access of data and the display of images are achieved. The system can also analyze the dynamic characteristics and the comfort of the occupant-seat system. By choosing different seat characteristics according to different vehicle environments, the best comfort can be obtained. In addition, it also provides some favorable references to the designing of safe and comfortable automobile seats.

Introduction

Car seat is an important part of the car. Its main function is to support the driver and the passenger's body, to reduce the impact on the body aroused by rough road surface and to attenuate the resulting vibrations. With the improvement of living standard and the rapid development of automobile technology, the demand for automotive comfort is higher and higher. Automotive comfort includes static and dynamic comfort. The former mainly involves size parameters, surface quality and the regulation characteristics; and the latter is largely related to vibration characteristics. In mechanical vibration test, because numerous complex test equipment are needed, a simple test may even require great manpower and large quantity of material resources, not to mention some complex work like the vibration test on car seats. With the development of computer and software technology, it is taking over the traditional method and is becoming the trend in the area of testing. In this article, a development platform based on LabVIEW software (a virtual instrument platform initiated by American National Instruments Company) is constructed. Necessary sensor, signal conditioners and data acquisition cards are taken as the main hardware to build a detecting and analyzing system for the seat vibration test. Results from experiments show that the suggested system can effectively fulfill the work of acquiring and processing seat vibration signals, analyzing its dynamic characteristics and assessing its comfort rate.

Overall system structure and working principle

Using virtual test instruments,the Virtual vibration testing and analyzing system completes the work of measuring, data analysis and processing of mechanical vibration signals. Totally resorting to computer software, it successfully achieves the functions of vibration signal acquisition, display, access and processing. The system structure is illustrated in Figure1. Hardware for the system includes: acceleration sensor, signal amplifier suitable for transfer, data acquisition card and PC machines. Its software is realized through graphic-oriented software LabVIEW.

The seat vibration test and analysis system first transforms the vibration signals detected by the sensor into analog signals, and then passed it to the signal conditioning. Next, the analog electronic signal is converted into digital signal by data acquisition card and finally is passed to the vibration test and analysis computer software for analysis.

The system realizes the seat vibration signal testing and data analysis via computer, which can completely replace the conventional signal analyzer and many other hardware devices to complete a variety of signal analysis and processing.

Designing of system functions

Based on the needs of seat vibration comfort testing, the main functions of this system include vibration signal acquisition and display, signal analysis and processing, dynamic characteristics analysis and comfort-rating assessment on seat vibration. Block diagram of the system function is shown in Figure 2.

Implementation and testing of system functions

Front panel of the seat vibration test system is shown in Figure 3, the functional modules can be switched freely through the option cards to achieve the functions of signal acquisition, signal processing, dynamic analysis and evaluation of comfort.

Vibration signal acquisition module

The system completes the external circuit signal acquisition through the DAQ assistant acquisition module and NI ELVIS external board. The acquisition results are shown in Figure 3. Besides filtering the signals, the module also has many other functions including frequency domain analysis, window processing, correlation analysis, FFT transform and etc.

Dynamics analysis module

The main function of car seats is to support the driver and the passenger's body, to reduce the impact of uneven road surface and to attenuate the resulting vibrations passed to the people, so as to provide a comfortable and safe riding condition. The kinetic parameters ---natural frequency and the damping ratio of the car seat, have a major impact on the damping properties of the seat. Thus, take a representative 1-DOF and 3-DOF occupant-seat model for dynamic analysis. Suggestions on how to choose dynamic parameters are also presented. The structure of 1-DOF and 3-DOF occupant-seat model is shown in figure 5.

In 1-DOF model, the human body is considered as a rigid body on the seat. Its frequency response function is:

2 2 2 2 ) 2 ( ) 1 ( ) 2 ( 1 | ) ( | ξγ γ ξγ ω + - + = H (1)
Where:

) 2 /( KM C = ξ is the damping ratio, M K / / ω γ =
is the frequency ratio.

The seat damping ratio and frequency ratio can be adjusted by changing the parameters of the car seat, so as to improve the frequency response of the seat.

M M K n + = ω , 1 1 1 / M K n = ω , 2 2 2 / M K n = ω , n ω ω γ / = , 1 1 / n ω ω γ = , 2 2 / n ω ω γ = , 1 2 (2 ( )) C K M M ξ = + , 1 1 1 1 (2 ) C KM ξ = , 2 2 2 2 (2 ) C K M ξ = , 1 1 1 2 ( ) M M M μ = + , 2 2 1 2 ( ) M M M μ = + ,
The frequency response function is:

) ( ) 2 1 ( 2 1 ) ( 2 2 1 1 B B j j H μ μ ξγ ξγ ω + - + + = (2)
Where:

1 1 2 1 1 1 1 2 1 2 1 γ ξ γ γ ξ j j B + - + = , 2 2 2 2 2 2 2 2 1 2 1 γ ξ γ γ ξ j j B + - + = .
When analyzing the simulation in LabVIEW, the parameters in the model are set on the following basis: 1) "Test Method of Car Seat Dynamic Comfort", in which the standard is M = 51kg ; 2) statistic results from domestic human body vibration test, in which M1 = 29.8kg, M2 = 5.5kg, K1 = 224.8N/cm, K2 = 133.1N/cm, C1 = 3.9N / (cm.s), C1 = 1.9N / (cm.s). The frequency response function of the two models is related not only to the parameters of the human body model but also to the natural frequency and damping ratio of the seat.

Figure 6 shows the system frequency response curve under different natural frequency and damping ratio of 1-DOF model, by which reasonable parameters can be chosen. The module can also analyze the displacement response curve of human body vibration by simulating different car environment and road condition. When different seat parameters are selected, the changes of human body vibration displacement can be directly observed, which will provide favorable reference for the design of safe and comfortable seats.

Seat comfort assessment module

The function of data analysis module is to analyze the collected and pretreated signals, so that the specific values of comfort can be obtained and car seat comfort can be measured. Data is processed using total RMS value of weighted acceleration comparison method by the data analysis module.

Taking into account individual's different sensitivity to the frequency of vibration, this method converts RMS acceleration which frequency ranges within 1 ~ 80Hz into RMS acceleration within sensitive frequency (4 ~ 8Hz, or 1 ~ 2Hz) by multiplying a different frequency weighting, then calculates the total acceleration RMS, and then sets the standard for evaluation: whether the corresponding limit exceeds ISO2631 sensitivity limit of the frequency or length of time As for the composite vibration condition which human body withstand from X, Y, Z three directions, we can first obtain respective frequency weighted RMS by calculating the acceleration spectra in each vibration direction, and then calculate the combined weighted acceleration value

A ω 。 2 2 2 ) ( ) 4 . 1 ( ) 4 . 1 ( ω ω ω ω z y x a a a A + + = (3)
Where: the factor of 1.4 is the most sensitive in the body within the same frequency range corresponding vertical and horizontal and vertical curve ratio.

"Total Travel Value Method" has been introduced in the draft of ISO2631/CD-1991, and the relationship between the acceleration value and the subjective feeling of the occupant has been given, as is shown in Table 1. The vibration signals from X, Y and Z direction are measured by the sensor. Then they are converted into vehicle vibration comfort indicators C ω and combined weighted RMS A ω through the program operation. Finally, the comfort condition is displayed on the front panel.

Conclusion

This system is actualized through a powerful graphical programming language LabVIEW and the existing hardware devices. It can measure seat vibration, process data, analyze seat dynamics characteristic and evaluate the driving comfort. Compared with traditional method, this system has the following advantages:

(1) Computer software program has replaced the traditional spectrum analyzers and other hardware devices. This system validates real-time analysis and processing, reduces test costs and shortens the test cycle.

(2) Resorting to the existing signal processing modules of LabVIEW to deal with vibration signals, the process is quicker and more accurate, and thus complex mathematic calculation is avoided.

(3) By making a dynamic simulation analysis on the human body -seat model, it provides a favorable reference to the designing of safe and comfortable seats. Based on ISO2631 standard, seat driving comfort is also evaluated.

Fig. 1 .

 1 Fig. 1. Schematic diagram of system structure

Fig. 2 .

 2 Fig. 2. Block diagram of the system function

Fig. 3 .

 3 Fig. 3. Front panel of the seat vibration test system

Fig. 4 .

 4 Fig. 4. Effect of filtering

Fig. 5 .

 5 Fig. 5. Structure of 1-DOF and 3-DOF occupant-seat model In 3-DOF model, the human body is considered as a 2-DOF dynamic model on the seat. Suppose: ) /( 2 1

Fig. 6 .

 6 Fig. 6. Frequency response curve under different damping ratio and natural frequency

Table 1 .

 1 Relationship between Acceleration Value and Subjective Feeling of the Occupant

	Weighted Acceleration Value(m/s 2 )	Subjective Feeling of the Occupant
	<0.0315	Comfortable
	0.315~0.63	slightly uncomfortable
	0.5~1.0	somewhat uncomfortable
	0.8~1.6	Uncomfortable
	1.25~2.5	very uncomfortable
	>2.0	Unbearably Uncomfortable

Acknowledgement. This work is supported by the Research Foundation of ECJTU (NO. 01308115), and Key Laboratory of Conveyance and Equipment.


Zhengping Liu

Shenghang Xu

Juanjuan Liu

Application of Interferometry in Ultrasonic System for Vibration

Keywords: Vibration Signal, Ultrasonic, Signal Processing, Fault Diagnosis

Vibration signals are important state parameters for mechanical equipments' status monitoring and fault diagnosis. In this paper, in order to overcome the limitations of the traditional vibration measurement med1ods and instrument, a new non-contacting vibration method based on ultrasonic for vibration detection in special environment was presented. The mainly researched in this paper were the circuit for ultrasonic transmitting, receiving, algorithm and the module based on LabVIEW for signal analysis and processing.

New algorithm was adopted in the system design. The measurement for vibration signals, which may have higher accuracy, was based on ultrasonic wave of different frequency. Experiments were carried on for proving the theory and the result was expected, verifying the reliability and feasibility of the system.

Introduction

Vibration signals are important state parameters for mechanical equipments status monitoring and fault diagnosis. The method of vibration signals measurement is very limited. Such as displacement sensor, speed sensor and acceleration sensor, they are limited of itself. Most of the sensors are mounted to measure the objects. Testing vibration on Eddy current sensor is a noncontact system, but the distance is very limited. The traditional vibration measurement med1ods and instrument can not achieve effective measurement in HTHP industrial environment. A new noncontacting vibration method based on ultrasonic for vibration detection is completed high precision, long-distance measuring in special environment. [START_REF] Yang | A Highly Accurate Ultrasonic Measurement System For Tremor Using Binary Ampltude-Shift-Keying And Phase-Shift Method[END_REF] To overcome the limitations of the traditional vibration instruments, a noncontacting vibration method based on ultrasonic for vibration detection in HTHP environment was presented in this paper. The noncontact system of vibration measurement is based on optical interferometry. Ultrasonic has advantages such as high frequency, shorter wave-length, steady direction of propagation, and easily obtainment of directional and focused ultrasound beam. The principle of the vibration measurement system is based on Doppler. A continuous wave ultrasonic beam is transmitted toward the vibrating surface, and the ultrasound signal reflected by this moving surface is sensed by a second transducer. The received ultrasound signal is phase modulated. Therefore, features can be extracted from the vibration signal by analyzing the factors that affect the variations of traffic load.

Method

The method of the vibration measurement system is based on the phase. The schematic diagram of the ultrasonic system for vibration measurements is given in the Fig. 1., y(t) and y(r) are respectively the transmit signal and the receive signal. In operation, the ultrasonic transmitter transmits y(t) continuously and the ultrasonic receiver will simultaneously receives y(r) reflected by the object. Besides, the w is the angular frequency of ultrasonic wave, the C is speed of ultrasonic wave, and the L(t) is distance between the ultrasonic transducers and the measured object. [START_REF] Yang | A Highly Accurate Ultrasonic Measurement System For Tremor Using Binary Ampltude-Shift-Keying And Phase-Shift Method[END_REF] The transmitted and the received wave forms are given by ) sin( ) (

φ + = wt r y ( 1
)
wt t y sin ) ( = (2)
The distance that the signal spreads from transmitting transducer to receiving transducer is 2 L(t). The L(t) depends on effective vibration length d(t). The change of phase Φ(t) is determined by the formula,

π λ φ 2 ) ( 2 ) ( * = t L t (3)
The effective vibration length is determined by the formula,

( ) ( ) ( λ π φ t t L t d ∆ = ∆ = ( 2 2 )
) 4
The λ is the wavelength of the ultrasonic wave used in this system; the Φ(t) is the change of phase and it is changed among 0 to π 2 ; the Φ(t) depends on the effective vibration length d(t). The peak amplitude dmax is peak amplitude of the ultrasonic wave. The θ has some repeated and the d(t) is not judged when the d(t) exceeds the length of λ/2. So the d(t) is bounded by λ/2 and the D(t) that it .the d(t) is bounded by λ/2 that is defect. To overcome this limitation, an effective algorithm was selected and low frequency wave and high frequency wave was adopted in this paper. The low frequency wave has large wavelength, so that the measurement range was increased.

The high frequency wave has high frequency, so that the measurement precision is improved. The total displacement D(t) is determined by the formula,

D(t)=2 λ π φ * ∆ = ∆ = 2 ) ( ) ( ) ( t t L t d = λ π θ λ * + * 2 n (5)
The θ 1 is the phase shift and its value usually cycles between zero to 2π. As shown in the Fig. 2., the D is the total displacement, the θ 1 is the phase, the λ 1 is the wavelength and the f 1 is frequency of the low frequency wave. The total displacement D(t) is determined by the formula, The θ 2 is the phase, the λ 2 is the wavelength and the f 2 is frequency of the low frequency wave. The θ 2 is a greater phase shift than phase frequency of the f 1 because the f 2 is greater than the f 1 . The integer number N 2 of wavelength of frequency f 2 signal can be calculated from N The final equation concluded from the above equations is shown as follows,

= ) (t D D 1 (t) =
2 =Int[D 1 /λ 2 ]. The total displacement D(t) is determined by the formula, D(t)=D 2 (t)=
L d T R d D 2 2π θ 1 θ 2 λ 2 D λ 1 n D(t)= Int[D 1 / 2 λ ]* 2 λ + 2 2 2 λ π θ * = Int[ 2 1 1 1 2 λ λ π θ * * ]* 2 λ + 2 2 2 λ π θ * = Int[ 1 2 1 2 f f * π θ ]* 2 f c + 2 2 2 f c * π θ (8)
where c is the speed of sound. The frequencies of 10 kHz and 40kHz are chosen in the experiment. So, the maximum distance is 1.70 cm. [START_REF] Yang | A Highly Accurate Ultrasonic Measurement System For Tremor Using Binary Ampltude-Shift-Keying And Phase-Shift Method[END_REF], [START_REF] Ngoi | An AcoustoOptic Vibrometer for Measurement of Vibration inUltraPrecision Machine Tools[END_REF], [START_REF] Han | Non-contact Damage Detection of a RotatingShaft Using theMagnetostrictive Effect[J][END_REF], [START_REF] Figueroa | An Ultrasonic Ranging System for Structural Vibration Measurements[END_REF]

The Hardware System Architecture

The hardware of the vibration measurement system consists of two ultrasonic transducers, for transmitting and receiving the signals, and the circui for ultrasonic transmitting and receiving signal processing. The part completes signal acquisition and processing function automatically.

Design of Transmission Circuit

The design of the circuit for ultrasonic transmitting adopted NE555 time-based circuit and also the peripheral circuits and the more harmonic oscillator circuit.The circuit of NE555 time-based worked for the setting and reset alternately repeatedly on without the steady-state operation mode. The 3 pin of output terminal is outputting utalternate with low level and high level, the output waveform approximated rectangular wave. There are many kinds of ultra harmonics of rectangular, therefore, the circuit without the steady-state operation mode can be called multi vibrator as self-excitation. [START_REF] Figueroa | An Ultrasonic Ranging System for Structural Vibration Measurements[END_REF], [START_REF] Bou Matar | Noncontact Measurement of Vibration Using Airborne Ultrasound ieee transactions on ultrasonics[END_REF] As shown in the Fig. 3., the circuit for ultrasonic transmitting consists of the circuit of NE555 time-based and the correlative circuit. The output of capacitor C 1 is unchanged. The 2 pin of NE555 outputs low level, the 3 pin of NE555 outputs high level and inward transistors are in off condition. The 7 pin is impending and the capacitor C 1 is charged by V DD . Then, the voltage of C 1 is building up. The V C1 reaches the threshold level 2V DD /3 after a time of T1. So, now the circuit of NE555 time-based has overturned and reseted. Then the 3 pin outputs low level, and the inward transistors are in conducting state. The 7 pin outputs low level, the capacitor C 1 is discharging. When the V C1 is droping to V DD /3 after T 2 , the circuit of NE555 time-based has overed and reseted, and the 3 pin outputs high level and the 7 pin is impending again, circulate down so. So the 3 pin can output a rectangular wave. The T1 of high-level outputs charging time is determined by the formula,

)] 3 / /( ) 3 / 2 ln[( ) ( 1 2 1 1 DD DD DD DD V V V V C R R t - - + - = 1 2 1 1 2 1 ) ( 693 . 0 2 ln ) ( C R R C R R + = + = (9)
Fig. 3. the circuit for ultrasonic transmitting.

The T2 of low-level outputs charging time is determined by the formula,

1 2 2 693 . 0 C R t = (10)
The cycle time of rectangular wave is determined by the formula,

1 2 1 2 1 ) 2 ( 693 . 0 C R R t t T + = + = (11)
The oscillation frequency f ,

1 2 1 ) 2 /( 44 . 1 / 1 C R R T f + ≈ = (12)
The dutyfactor D of output pulse is determined by the formula,

) 2 /( ) ( 2 1 2 1 R R R R D + + = (13)
The output is a square wave signals when the R 2 is much greater than the R 1 and the duty factor D equals to 50%.

The oscillation frequency f is up to R 1 and R 2 to determine. Center-frequencys of the ultrasonic transmitter are respectively 40 kHz, 10 kHz. When the center-frequency is 40kHz, the C 1 is 0.1 μ F, and the resistances of R 1 and R 2 are respectively 0.6k Ω and 1.5k Ω . When the center-frequency is 10kHz, the C 1 is 0.1 μ F, Resistances of R 1 and R 2 are respectively 1k Ω and 72k Ω .

Design of Receiving Circuit

As show in the Fig. 4., the circuit for ultrasonic receiving, that in which signal amplification, filtering, DC signal eliminating are included, has function of signal processing, avoiding the shortcomings of feeble signal and noise. The 2 stage signal amplification system was adopted in this experiment. The signal that is processed is deduced to PC computer. The signal can be shown by the software system.

The circuit for ultrasonic receiving can be used in combination with the circuit for ultrasonic transmitting. The circuit is composed of four parts: the amplifying circuits A 1 and A 2 , the rectifying circuit R 3 , the filter circuit RC, and the comparator circuit A 4 .

The filter circuit has frequency selectivity that it amplifies 40 kHz signal and the yield value equals to 5. Multistage filter circuit was adopted. The half-wave rectifying circuit consists of operational amplifiers. The cut-off frequency of the filter circuit is 40 kHz. The comparator circuit also consists of operational amplifiers.

Testing

The system for experiment was composed of three parts: the hardware of the system, the interface circuit and the software of the system. The experimental facility included a flexible manipulator, a vibration exciter, two ultrasonic transducers, various circuits and a data acquisition card. The vibration source consists of the flexible manipulator that was driven by vibration exciter. The vibration exciter was adjusted among 20 to 20 kHz.The date was gathered by the multifunction data acquisition card which is made in the NI Company.

The system of software can realize the real-time signal ongoing acquisition and storage. The change of phase is transformed into the visualization function graphic of D(t). The software extracted effectively characteristic value of the vibration signal. [START_REF] Figueroa | An Ultrasonic Ranging System for Structural Vibration Measurements[END_REF][START_REF] Bou Matar | Noncontact Measurement of Vibration Using Airborne Ultrasound ieee transactions on ultrasonics[END_REF] The frequency of the excitation signal in the experiment was selected at 71.2Hz. The irregular original signal was provided in Fig. 5. In addition, Fig. 6. gives the changing law of phase-shifts. After the collection and analysis of the phase-shifts change, completed vibration signal will be obtained, as well as the characteristic value. However, when the amplitude of the flexible manipulator is too large, the changing signal of phase shift signals confusion and cannot be measured then, as show in Fig. 7.

Conclusion

With the new system, which is based on vibration detection with ultrasonic wave, designed in this paper, remote objects can be detected on the vibration, overcoming the limitations that contact measurement has, such as piezoelectric sensors etc. The new system can also be applied to low frequency vibration measurements, with a much wider measurement range than the eddy current sensor. Here, no accessory is needed to be mounted on the vibrating object, avoiding the influence of vibration objects. The measurement technique based on the ultrasonic wave is a supplement for non-contact vibration measurements. It has many advantages such as low cost, convenient operation, high test speed, and so on. So that this measurement technique has much potential applicative value for condition monitoring of some industrial machinery equipments, especially for application in vibration measurement of fine structure or in some special working environment, such as high temperature, high pressure, dust, strong corruption, non-Contact and so on. Certainly, there are some shortcomings of this measurement technique. Great restrictions are still existed for the amplitude of vibration, not being solved completely. Continue study and further improvement are still needed in the future.

Fig. 1 .

 1 Fig.1. Schematic diagram of ultrasonic system for vibration measurements.

Fig. 2 .

 2 Fig. 2. Schematic diagram of the method.

Fig. 4 .

 4 Fig.4. the circuit for ultrasonic receiving.

Fig. 5 .

 5 Fig.5. Original signal oscillogram.

Fig. 6 .

 6 Fig.6. Phase-shifts D(t) oscillogram.

Fig. 7 .

 7 Fig.7. phase-shifts D(t) oscillogram when the amplitude is too large.


Chunsheng 罗春生

Luo

薛龙 Long Xue

刘木华 Muhua Liu

Jing 黎静

Li

王晓 Xiao Wang

Nondestructive measurement of sugar content in navel orange based on Vis-NIR spectroscopy

Keywords:

The Vis-NIR spectroscopy technology was studied on nondestructive measurement of sugar content in navel orange. Three different spectral ranges of 450-1000nm,1000-1800nm and 450-1800nm were selected, respectively and five different spectral pre-processing methods of Standard Normal Variate (SNV), first derivative (FD), second derivative (SD), multiplicative scatter correction (MSC) and smoothing were used for establishing the partial least squares(PLS)models, which was determined the sugar content in navel orange.

The results showed that the model developed from 450-1800nm spectroscopy after SNV pre-processing achieved the optimal performance. The correlation coefficient (r 2 ) of the calibration set and validation set were 0.9349 and 0.8514 respectively, and the root mean squared error of calibration and validation sets were 0.8017 and 1.1649, respectively. The research indicated that the Vis-NIR spectroscopy technique was feasible to nondestructive measurement of sugar content in navel orange.

Introduction

Currently, the fresh fruit need to meet certain quality grade requirements before they are shipped to the marketplace. These requirements include fruit outward characteristics (i.e. size, color, and shape) and internal quality attributes (sugar, acid, firmness,etc.). With the continuous improvement of people's living standard, the quality requirements of fruit are more and more focus on internal quality attributes.

As a quality attribute of fruits, sugar content will directly impacts on consumers' purchase demand。 Visible-Near infrared spectroscopy (Vis-NIRs) is one of the fastest growing analytical technologies in recent years. It has several advantages compared to traditional chemical methods: speed, non-destructed of sample, avoidance of the use of chemicals and simplicity of sample preparation. Researchers have shown for years that Vis-NIR spectroscopy is a suitable technique for sugar content measurement in various fruits: nectarine [START_REF] Xiaoqiang | A Study on Non-destructive Measurement of Nectarine Sugar Content by Means of Spectral Imaging[END_REF] , apple [START_REF] Zhaoshen | Improving Apple Fruit Quality Predictions by Effective Correction of Vis-NIR Laser Diffuse Reflecting Images[END_REF][START_REF] Zhao Jiewen | Non-destructive determination of sugar contents of apples using near infrared diffuse reflectance[END_REF][START_REF] Zhao Jiewen | Preprocessing Methods of NearInfrared Spectra for Simplifying Prediction Model of Sugar Content of Apples[END_REF][START_REF] Dengsheng | A Quick and Non-destructive Measurement of Soluble Solids Content of Apple Based on Visible/Near Infrared Spectroscopy[END_REF] , Nanfeng mandarin [START_REF] Yangde | Analysis of Soluble Solid Content in Nanfeng mandarin fruit with Visible Near infrared spectroscopy[END_REF] , and citrus [START_REF] Huishan | Estimation of Soluble Solids Content of Intact Citrus Fruit by Vis/NIR Spectroscopy[END_REF] . Vis-NIR was also used for measurement the quality attributes of tea [START_REF] Zhao J Iewen | Feasibility Study on Use of Near-Infrared Spectroscopy in Quantitative Analys is of Catechins in Green Tea[END_REF] , Chlorophyll [START_REF] Li Qingbo | Chlorophyll Content Nondestructive M easurement M ethod Based on Vis/NIR Spectroscopy[END_REF] , pork [START_REF] Kuiwu | Visible/NIR Analysis of Fat,Protein and Water in Chilled Pork[END_REF] , etc. The development of equipment with improved electronic and optical components and the advent of computers capable of effectively processing the information contained in Vis-NIR spectra has facilitated the expansion of this technique in an increasing number of fields. This paper focuses on the navel orange sugar content results obtained by using different spectral ranges and different spectral pre-processing methods to establish the validation models of partial least squares (PLS).

Materials and Methods

Navel orange samples

Two hundred and seventy navel orange samples were used for the experiment. These navel oranges were harvested from an orchard at Ningdu county, Jiangxi province, China. The samples were placed at room temperature (10℃) and relative humidity (60%) for 168h before the experiment. Total of samples were divided into two groups: 185 samples were designed as calibration models set for model development and the remaining as validation set for validation. The selection of samples for calibration and validation was random and the samples' sugar content of validation was among the region of calibration samples' sugar content.

Vis-NIR Imaging System

Figure1 shows the Vis-NIRs imaging system. The system mainly consisted of an imaging spectrograph QualitySpec Pro (Analytical Spectral Devices, Inc., USA) with a spectral range from 350nm to 1800nm, appropriate lighting sources, optical fiber and a computer. Spectra of the samples were obtained with 1nm interval and scan frequency was 10 times. Indico software (version 4.0, Analytical Spectral Devices, Inc., USA) was used for spectra data. Each navel orange was measured 6 times, rotating 60° was taken on the equatorial zone of the navel orange. The average of the 6 measurements was used later for date processing. In the measurement, note that to prevent light leakage and avoid scratches, scars and other surface defects as much as possible.

Experimental procedure

After the imaging, Extracted juice of each navel orange flesh was filtered and then taken for sugar content measurement by a digital refractometer (Model PR-101,Atago Co. Ltd, Tokyo, Japan). Each sample was measured 9 times with the squeezing juice.

The average of the 9 measurements was used later for date processing.

Spectral data Processing

The raw Vis-NIR spectral profiles of navel oranges are shown in figure 2. It can be seen that the spectra contain a lot of noises from wavelengths between 350 to 449nm, and absorption peak due to water around 1000nm. Thus, the raw spectrum was divided into three different spectral ranges: 450-1000nm, 1000-1800nm and 450-1800nm, and then five different spectral pre-processing methods of standard orthogonal variable transformation (SNV), first derivative (FD), second derivative (SD), multiplicative scatter correction (MSC) and smoothing were used. Spectral pre-processing of raw spectra data were applied to all measured spectra to reduce the effects of high-frequency random noise, baseline drift, sample particle size and light scattering etc, which can effectively adjust near-infrared spectrum [START_REF] Wanzhen | Modern Near Infrared Spectroscopy Analytical Technology.Beijing:China Petrochemical Press[END_REF] . Spectra from the Indico software were exported to suitable format.

Result and Discussion

Pre-processing methods

Partial least squares (PLS) is a very popular regression method in application of

Vis-NIR spectroscopy. In this study, PLS regression combined with spectral pre-processing such as derivative, standard normal variate transformation (SNV), multiplicative scatter correction (MSC) and smoothing was used to develop calibration models. PLS analysis was carried out to determine the optimal set of wavelengths and to develop calibration models using the statistical software Unscrambler.

Calibration models were compared using the root mean squared error of calibration (RMSEC), root mean squared error of prediction (RMSEP), and correlation coefficients (r 2 ) for calibration and validation. A good model should have a low RMSEC, a low RMSEP and a high r 2 value. The calculation of RMSEC indicated how well the model fits the calibration data, and the parameter of RMSEP was reported as an indication of the model validation capability. RMSEC and RMSEP were calculated based on the following formulas:

Where:I C ---number of samples in the calibration set; I P ---number of samples in the validation set; i y -----measured value of the i th sample; i y ∧ -----predicted value of the i th sample;

Calibration and Validation Models

Table 1 shows the PLS models results of different pre-processing methods and spectral ranges. The best wavelength range was from 450 to 1800 nm, which was wider than the other two wavelength ranges (450~1000 nm and 1000~1800 nm). It covers the visible and NIR spectral regions. Comparing the results in table 1, it shows that the optimal PLS model is obtained in the range of 450-1800nm and by the spectral data preprocessing method of SNV. For calibration, the correlation coefficient r 2 and the RMSEC is 0.8514 and 0.8017 respectively. For validation, the correlation coefficient r 2 and the RMSEP is 0.8514, and 1.1649 respectively. Figure 3 shows the calibration result using PLS and SNV spectral pre-processing in the wavelength range of 450-1800nm for 185 intact navel oranges with a calibration correlation coefficient r 2 of 0.8514 , a RMSEC of 0.8017 and figure 4 shows the validation result for the left 85 samples with a validation correlation coefficient r 2 of 0.8514, a RMSEP of 1.1649. As the error that happened in chemical test and instruments, the result of validation was not good enough, so the next step research is to change the method to improve the predict capability. It was concluded that Vis-NIR reflection method yields a satisfied estimate of sugar content value in intact navel orange.

Conclusions

This research indicated that it is possible to develop a nondestructive method for measuring the navel orange sugar content by Vis-NIR spectroscopy. The results

showed that the PLS model developed from 450-1800nm spectroscopy after SNV pre-processing method achieved the optimal performance. The correlation coefficient (r2)of the optimal model of the calibration set and validation set were 0.9349 and 0.8514 respectively and root mean squared error of calibration and root mean squared error of validation were 0.8017 and 1.1649 respectively. It can be concluded that VIS/NIR spectroscopy could be a reliable, accurate, and fast method for measurements sugar content of navel orange.

Fig. 1 .

 1 Fig.1. Vis-NIRs system

Fig 2 .

 2 Fig 2. Raw spectra of navel oranges Software Unscrambler (version 9.7, CAMO AS, Trondheim, Norway) and Matlab 7.1(Mathworks, Inc., USA) were used to analysis Vis-NIR spectroscopic data.

Fig. 3 .Fig. 4 .

 34 Fig.3. the optimal model of the calibration set

Table 1

 1 PLS models results of different pre-processing methods and spectral ranges

	Wavelength Range/nm	Spectral Pre-processing Method	Factors	r 2	Calibration RMSEC	r 2	Validation RMSEP
	450~1800	SNV	17	0.9349	0.8017	0.8514	1.1649
		FD	7	0.8556	1.1941	0.8063	1.3302
		SD	6	0.7885	1.4452	0.6972	1.6630
		MSC	18	0.9397	0.7718	0.8434	1.1960
		Smoothing	19	0.9315	0.8224	0.8305	1.2443
	450~1000	SNV	13	0.8875	1.0587	0.7739	1.4372
		FD	5	0.8044	1.3900	0.7924	1.3772
		SD	6	0.7634	1.5287	0.7056	1.6340
		MSC	14	0.9020	0.9840	0.8000	1.3514
		Smoothing	13	0.8894	1.0451	0.7691	1.4524
	1000~1800	SNV	14	0.8857	1.0627	0.8471	1.1819
		FD	7	0.8889	1.0475	0.7634	1.4700
		SD	5	0.8854	1.0639	0.5272	2.0780
		MSC	14	0.8853	1.0644	0.8475	1.1804
		Smoothing	15	0.8728	1.1209	0.8505	1.1684

Acknowledgement

This work was supported in part by the National Natural Science Foundation of China (No. 30760101) ,Jiangxi Provincial Department of Science and Technology (No. 2009BNB05705) and Jiangxi Provincial Department of Education (No.GGJ08513).