Eiichi Taniguchi

Prof. Rémy Laetitia Dablanc

Prof Dupas

Prof Assoc Jesus Gonzalez-Feliu

Ms Jean- Christophe Diana Deschamps

In Dizian

Prof France

Michael Browne

Prof Sweden

Ron Van Duin

City logistics for sustainable and liveable cities

Keywords: City logistics, Emerging technologies, Public-private collaborations, Data sharing, Urban consolidation centres, Modelling status, issues and benefits 3.3. Discussions 4.2 Current status, issues and innovative solutions 4.2 City logistics, Emerging technologies, Public-private collaborations, Data sharing, Urban consolidation centres, Modelling

This discussion paper tackles the complicated and important problems of city logistics or urban freight transport for sustainable and liveable cities. It focuses on the use of emerging technologies including Information and Communication Technologies (ICT), Intelligent Transport Systems (ITS), Internet of Things (IoT), big data, Artificial Intelligence (AI), autonomous vehicles, and robots as well as the public-private collaborations of stakeholders. It clarifies the innovative solutions for urban freight transport issues for sustainable and liveable cities based on the experiences of planning, modelling, and evaluating policy measures, strategies, and management of city logistics in Europe, Japan, and Australia. The paper discusses the important factors for promoting city logistics such as the integrated platform, data sharing between public and private sectors, urban consolidation centres, multi-agent simulations, use of autonomous vehicles, and public-private partnerships. It concludes that the collaborations between stakeholders are critical for successful implementation of city logistics initiatives, and modelling city logistics using the simulation and optimisation techniques based on the emerging technologies is essential to anticipate the effects of policy measures and benefits for each stakeholder to make proper decisions.

Introduction

Urban freight transport is important for economic growth and sustainable environment and liveability of cities. The movements of goods and freight vehicles in urban areas have increased due to the increase of e-commerce and other economic activities. However, we face difficult problems of higher costs for urban goods delivery, nuisance including traffic congestion, crashes, Green House Gas (GHG) emissions, local emissions, noise and vibration. For tackling these difficult issues, city logistics have been proposed (Taniguchi et al., 2001) and implemented in several cities around the world. City logistics provides innovative solutions for urban freight transport issues using emerging technologies of Information and Communication Technologies (ICT), Intelligent Transport Systems (ITS), Internet of Things (IoT), big data, Artificial Intelligence (AI), autonomous vehicles, robots and others (Taniguchi et al., 2020a). As many stakeholders such as shippers, freight carriers, administrators, and residents are involved in city logistics, collaborations among these stakeholders are essential for successful implementation of city logistics policy measures.

The research subject "city logistics" itself is interdisciplinary which requires wide ranged approaches from transport and logistics engineering, informatics, economics, public policy, geography, management, and others. The discipline of city logistics is aiming at balancing the economic growth and the social wellbeing of environmental friendliness, safety, security, and energy efficiency in urban areas. City logistics has three goals (Figure 1.1): mobility, sustainability, and liveability. The objectives of city logistics encompass the reduction of logistics costs as well as the decrease of traffic congestion, greenhouse gas (GHG) emissions and other negative environmental impacts, and energy consumption, and the improvement of safety and security in community. Therefore, we need to do interdisciplinary studies for tackling the complicated urban freight transport issues.

Figure 1.1 Three goals of city logistics

In the following, Section 2 presents literature reviews of important topics in city logistics.

Section 3 highlights data sharing between public sectors and private companies in Europe, Japan, and Australia, discussing the issues and opportunities for sustainable city logistics.

Section 4 covers recent advances of city logistics in Europe, Japan, and Australia, looking into the insights of city logistics in terms of the use of emerging technologies, policy measures, modelling, and the public-private collaborations. Section 5 gives concluding remarks.

Literature review

Overview

City logistics using recent innovative technologies including ITS (Intelligent Transport Systems), ICT (Information and Communication Technology), IoT (Internet of Things), big data and AI (Artificial Intelligence), autonomous vehicles, and robots is promising for evolving smart city logistics. Vehicle routing and scheduling with time windows models, multi-agent models, multi-actor multi-criteria models, and location routing models have been studied and applied in a great number of case studies for sustainable urban freight transport. Evaluating the city logistics policy measures using these mathematical models is required to understand their effects before implementing them in advance. As several stakeholders including freight carriers, shippers, administrators, and residents have different objectives, the evaluation using multiple criteria was often executed. The literature review is given below on the important topics in city logistics.

Use of emerging technologies including ICT, ITS, IoT, big data, and AI

Emerging technologies including ICT, ITS, IoT, big data, and AI are useful for establishing smart city logistics. (Taniguchi and Thompson, 2014). These technologies allow an integrated platform for managing urban freight transport systems to be provided and operated in urban areas. The function of ITS and ICT includes: Integrated platforms can provide benefits such as improving the efficiency of urban deliveries and reducing CO 2 footprints. pandemic [START_REF] Chen | The adoption of self-driving delivery robots in last mile logistics[END_REF]. [START_REF] Figliozzi | Autonomous delivery robots and their potential impacts on urban freight energy consumption and emissions[END_REF] showed the autonomous delivery robots have the potential for significantly reducing the energy consumption and CO2 emissions. Discussing the effects of policy measures before implementing them as well as after the implementation is important among stakeholders in the PPP. Modelling city logistics helps discussions and decision making by providing the estimation of responses of shippers and freight carriers to policy measures taken by a municipality and their impacts on urban traffic and environment. Katsela and Palsson (2020) presented a multi-criteria decision model using analytic hierarchy process to support stakeholder management in city logistics.

Autonomous vehicles and robots for last mile delivery

Collaborations between stakeholders

Multi-agent simulation

Multi-agent modelling provides us with a useful tool for representing and understanding behaviour of stakeholders, i.e., shippers, freight carriers, administrators, and residents who are involved in city logistics. Collaboration between stakeholders is essential for successful operation of city logistics and a multi-agent simulation allows us to predict the effects of city logistics policy measures before implementing them in real urban areas and to find appropriate management for satisfying the objectives of stakeholders. Smart city logistics are based on advanced information systems and this aspect can be incorporated in multi-agent simulation. green management and parking management. They pointed out that in public-private partnerships (PPP), multi-agent models will play an important role for evaluating city logistics policy measures based on data. Sharing data from both the public and private sectors is essential and interaction between both sectors is necessary to find better solutions using the results provided by multi-agent simulation.

Multi-agent models can be used for multi-stakeholder decision making based on this modelling approach. Le Pira et al. ( 2017) applied integrated models of discrete choice models (DCM) with agent-based models (ABM). These models consider stakeholders' heterogeneous preferences and simulate their interactive behaviour in a consensus building process. They pointed out that the integrated models of DCM and ABM can overcome their weaknesses, since it is grounded on sound microeconomic theory providing a detailed (static) stakeholders' behavioural knowledge, but it is also capable of reproducing agents' (dynamic) interaction during the decision-making process. [START_REF] Lebeau | Improving policy support in City Logistics: The contributions of a multi-actor multi-criteria analysis[END_REF] presented the multi-actor multi-criteria analysis (MAMCA) as a method which structured the consultation process of stakeholders in city logistics. They tested this approach in a workshop in Brussels and concluded that the methodology allowed the authorities to identify the priorities of the stakeholders in City Logistics, to guide the discussion towards a consensus and to provide inputs for an eventual adoption of strategies. [START_REF] Gatta | Planning with stakeholders: Analysing alternative off-hour delivery solutions via an interactive multi-criteria approach[END_REF] applied an interactive MAMCA for analysing off-hour delivery (OHD) solutions with stakeholders in Rome. They pointed out that stakeholders prefer a solution where OHD are jointly implemented together with one or more urban consolidation centres.

Data sharing between public sectors and private companies in some cities in Europe, Japan and Australia

Overview

The data sharing between public sectors and private companies is important for modelling, planning and evaluating policy measures related to city logistics. Recently ITS (Intelligent Transport Systems), ICT (Information and Communication Technologies), and IoT (Internet of Things) allows private logistics companies to obtain precise data on movements of vehicles and goods, location of depots and demands for delivering goods. Public sector traditionally owns data on traffic congestion, crashes, emissions of CO2, NOx and PM, and infrastructure provision. Data sharing within stakeholders is beneficial for understanding the current status and planning sustainable urban freight transport in the framework of public-private partnerships. However, there are issues of confidentiality of logistics companies, costs of collecting data, regulations by law and lack of tools for analysing data.

To exchange knowledge and discuss these topics, we conducted a workshop online on 19 th November 2020 on "Data sharing between public sectors and private companies for developing policies in city logistics." Twelve professors and researchers who are actively doing research in city logistics area participated in the workshop from France, Sweden, The Netherlands, UK, Australia and Japan. We had six presentations and intensive discussions on the issues and barriers, benefits for stakeholders, framework associated with data sharing between public and private companies for city logistics. The following sections highlight essential points on the topics based on case studies in France, Sweden, The Netherlands, UK, Japan, and Australia and discussions in the workshop. We also had an interview to a person who are in charge of urban freight planning in City of Rotterdam, on data sharing with private companies in The Netherlands.

Current status, issues and benefits

The data sharing between public sectors and private companies is essential for understanding the current status of urban freight transport. In Rotterdam, the Netherlands, the data sharing for improving urban freight transport is performed among City of Rotterdam, 56 private companies, and two universities [START_REF] Duin | Policies in Rotterdam, Workshop on data sharing of public sectors and private companies for developing policies in city logistics[END_REF].

The covenant of data sharing between City of Rotterdam and 56 companies was signed in 2020, including receivers, transporters, shippers, retailers, financial service providers, vehicle manufacturers and think tank. Figure 3.1 shows the data sharing scheme in Rotterdam.

Universities take part in carrying out urban freight flow simulation using the data provided by private companies. In Australia, Bureau of Infrastructure, Transport & Regional Economics (BITRE) made

Non-Disclosure Agreement with some transport companies and obtained truck GPS (Global Positioning System) data (Thompson, 2020). The government uses these data for understanding the traffic congestion and analyse them for better traffic management and infrastructure provision.

In In Sweden, sharing data, knowledge and visions is performed between public and private sectors. For example, in Gothenburg some industry and public data are combined for better understanding and planning of transport infrastructure [START_REF] Flodén | Data sharing between public sectors and private companies, Workshop on data sharing of public sectors and private companies for developing policies in city logistics[END_REF].

Discussions

There is a large variety of data sharing between public and private sectors for urban freight transport in different countries due to laws, cultures, and businesses environment.

Collaboration in data sharing is beneficial for both public and private sectors in the context of public-private partnerships in urban freight transport. For public sectors, they can utilise real data of logistics activities of private companies for developing policies on urban freight transport. For private companies they can enjoy lower costs for data collection and usage.

If data are already provided in standardised format, they can easily use data for collaborative delivery with other companies.

Regarding the confidentiality of private companies' data, the covenant between public sectors and private companies is effective to allow the public sector to use a company's data but not open them to other competitive companies. This type of covenant is needed to ensure the confidentiality of private companies. If some companies agree to operate joint delivery system, for example, it is welcome to use data of multiple companies who take part in the joint delivery systems. Therefore, the clear agreement and covenant promote reliable and effective initiatives.

In Sweden, when private data are given to public sectors, the data may be legally recognised as "official records" which mean to be accessible for the public. This may be a reason for private companies not willing to be involved in data sharing with the public sector.

Shared data should be under the trusted party and the public authority may not be a trusted party, if the public authority need to open the shared data coming from private companies to the public.

Data sharing between public and private sectors is usually volunteer based schemes. In certain cases of The Netherlands, Japan and Australia volunteer-based data sharing is successfully carried out. The incentives for private companies to be involved in data sharing with public sectors and other private companies may be lower costs for collecting data, access to better software for analysing data, and use of standardised format of data.

In city logistics data sharing is a part of public private partnerships (PPP) between stakeholders. Therefore, based on data sharing, the stakeholders are able to understand the current condition of urban freight transport, analyse the policy measures, implement them and evaluate their effects. The total activities in PPP should be well coordinated. In this sense the limitation of data affects the analyses and results and then sharing data can overcome the limitation of data of a single entity.

Regarding the quality of data, somebody or some institutions should guarantee the quality of data. The standardisation of the method for collecting and processing data is critical for analyses. Usually, we face missing data in spatial and temporal data of urban freight transport.

How we can extrapolate the missing data is an important problem for obtaining the good results with higher accuracy.

In the time of COVID-19 pandemic, data sharing is important between stakeholders, since the worldwide pandemic is the first time, and we face the difficulty to estimate the sudden change of demands of customers. Also, as there is uncertainty of estimating the behaviour of customers in the pandemic, we need to share data and experience associated with urban deliveries.

Recent advances of city logistics in Europe, Japan and Australia

Overview

This section presents discussions and perspectives on the recent advances of city logistics for sustainable and liveable cities based on the final workshop organised by FFJ/Michelin Foundations on 25 th January 2021. Nine speakers from Europe, Japan and Australia participated in the workshop and presented recent advances of the research in modelling, planning and evaluating city logistics and discuss issues and innovative solutions associated with urban freight transport for sustainable and liveable cities.

Current status, issues and innovative solutions

Japan

Taniguchi (2021) presented the framework of the integrated platform of city logistics shown in Figure 4.1. In the integrated platform the information systems in the cyber space and the real vehicle operations in the transport network can be integrated and multimodal freight transport is used. The integrated platform can be achieved by the support of emerging technologies of ICT, ITS, IoT, big data, AI, autonomous vehicles, and robots as well as the public-private collaborations including the use of urban consolidation centres, multimodal freight transport and data sharing.

The emerging technologies allows us to take a data driven approach. Figure 4.2 illustrates the data driven approach for city logistics using multi-agent simulations. We can collect data on demands of customers, vehicle types, and traffic conditions using IoT sensors and process them.

Then we can analyse the behaviour of stakeholders of shippers, freight carriers, administrators, and residents using the behaviour models and AI or machine learning techniques. The analyses involve the response of logistics companies to the policy measures implemented by the administrators and the effects of applying autonomous vehicles for last mile delivery. Finally, the evaluation can be done on the output of vehicle movements, emissions of GHG and NOx, energy consumption, and costs. The system can provide good services to customers such that they can receive their commodities within the designated arriving time windows of 10 minutes and the information will be given in their smart phone when autonomous vehicle is approaching the delivery point.

Customers are allowed to identify any location where they hope to receive their goods. The possible benefits of using autonomous vehicles for urban distributions are:

(a) Reduce the total costs of the initial costs and running costs, since no drivers are needed for fully autonomous vehicle operations.

(b) Provide a flexible system to meet with the rapid change of demands by customers.

(c) Solve a problem of shortage of drivers.

(d) Avoid a re-delivery due to the absence of receivers.

(e) Provide a better service such as deliver goods anywhere, anytime at short time windows.

(f) Provide a new service of delivering goods at a meeting point on streets or following a walking person.

(g) Lower risk of infection due to contactless delivery in the pandemic times.

(h) Connect with other transport modes of trains, barges, and drones.

(i) Carry out multiple tasks including watching elderly people, disinfection spraying, cleaning.

There are also issues of using autonomous vehicle for urban delivery, which should be overcome.

(a) High initial costs of purchasing autonomous vehicles or robots.

(b) Acceptability of customers and citizens in terms of price, reliability, safety and security.

(c) Regulations on the size, speed, payload of autonomous vehicles, and going on sidewalk and stopping locations on streets.

(d) Concern about taking away jobs from drivers.

(e) Limitation of range and payloads of autonomous vehicles and robots.

(f) Location of micro hubs or moving hubs for two echelon delivery systems.

(g) Provision of infrastructure of charging stations of electricity, and smooth surface of pavement (h) Appropriate stopping points on roads.

Regarding the collaborations between stakeholders, the joint delivery systems using urban consolidation centres (UCC) (Taniguchi and van der Heijden, 2000) are implemented in Tokyo. delivering parcels to the same destinations. Figure 4.12 highlights effects of the pooling of goods and the integration of UCCs. This figure indicates that both the pooling and the integration are effective in reducing the total distance travelled by pick-delivery trucks. The total distance with the full integration was reduced by 18.3% in the case of no pooling and that with the pooling was reduced by 11.7%. The total distance with the pooling and full integration was reduce by 50.1% compared to the case without pooling and integration. Therefore, the collaborations between freight carriers by sharing the capacity of trucks and UCC are effective to decrease the total distance travelled which leads to the cost saving and the improvement of environment.

France

Dablanc (2021) presented innovations in city logistics in the case of France. According to the comprehensive urban freight survey in France, one delivery or pick-up is carried out per week. On the vehicle type, smaller vehicles or cargo bikes are used in urban areas. Urban freight data are still missing. In particular no plate-reading cameras are used in France on traffic/parking enforcement. Provision of data from freight operators is only emerging.

Regarding pick-up points of parcels, "home and in hands" is the first (27%) and "in a pickup point" (21%), "in mailbox" (15%) and "to doorman" (12%) follows in 2018. Pickup points in small stores show a new trend of receiving form of goods in urban areas.

CO2 emissions from urban freight decrease 18% between 2004 and 2014 according to the official carbon footprint assessment of City of Paris.

Low emission zones (LEZ) are popular policy measures in EU, but in France implementing LEZ is later and slower than in other European countries. For greater Paris metropolitan wide LEZs are introduced in 2019 but it is difficult to enforce the regulations to vehicles, since no permission of using cameras is given for automatic enforcement until 2021. Only 70 municipalities out of 130 signed to agree the regulation.

The cycle logistics using cargo bikes is substantially increasing in large cities. In the COVID-19 pandemic time the access to bike lanes is the main advantage.

The electric vans increased only by 10% much slower than in electric cars by 159% in They calculated parcels flow using the multi-commodity network flow model, which was applied in the case study in Tokyo [START_REF] Dupas | A multi-commodity network flow model for sustainable performance evaluation in city logistics: Application to the distribution of multi-tenant buildings in Tokyo[END_REF]. They found that the total distance travelled by small trucks from depots of freight carriers to UCC and from UCC to PLS was reduced by 51% with the pooling of vehicle capacities and the full integrations of UCC compared with the no pooling and partial integration of UCC. The results of the reduction of total distance travelled is like the case of Tokyo. In the cases of Bordeaux, the effects of pooling are larger than those of integration of UCC. They also highlighted the reduction of CO 2 emissions by 35%.

Gonzalez-Feliu (2021) discussed the Territorial Intelligence approach to support decision making in urban planning and food logistics. He proposed the methodology of Territorial

Intelligence approach. This approach accounts for the logistics intensity and attractiveness of food supply in urban activities via Territorial Intelligence Indicators such as economic, environmental, socio-spatial and resilience and vulnerability indicators.

He applied the Territorial Intelligence approach in La Rochelle, France and demonstrated the important food demand generator indicating that the local fixed marketplace represents 40-60% of the food supply of the proximity retailers. HoReCa (Hotel/Restaurant/Café) sector has more homogeneous distribution in the city. He concluded that spatial analytics using Territorial Intelligence approach allow us to better understand current situations and can lead to a more relevant decision support methods and tools. Other solutions are considered in the research practice, including trucks on hydrogen, drone delivery for medicines, cargo hitching using passenger transport of buses, subways, trams, cargo bots using autonomous vehicles, sharing logistics, and physical internet.

The Netherlands

Sweden and UK

Browne (2021) discussed the importance of stakeholder engagement and trust in data sharing for city logistics. We can find dramatic increase in data availability connected to urban freight and logistics, but many barriers exist to sharing data between private sectors and public authorities, for example, legal issues, competition, privacy and civil liberties, cost sharing etc.

Some suggestions are given how they can be overcome through regulations, subventions, access CLFQP tries to understand freight and logistics issues in central London for finding sustainable solutions for fright and services with sharing good practices. The members of CLFQP are some boroughs, TfL, Freight Transportation Association, and private logistics companies.

These two networks are related to topics, including information on future transport changes, changing the access arrangements for streets for result of decisions to increase space for walking and cycling, sharing information on changes of deliveries from changes in transport and logistics resulting from the COVID-19 pandemic.

Browne (2021) concluded as follows associated with the importance of stakeholder engagement.

(a) A central activity that needs to form the part of strategy that increase data sharing in city logistics.

(b) Builds trust, overcomes inertia within and between private sector organisations and public authorities.

(c) Freight networks and partnerships offer a very helpful platform or starting point.

(d) Potential to enable more rapid development of data sharing initiatives.

(e) More is happening than we appreciate but, in many cases, this is not coordinated and retained. [START_REF] Leonardi | Does 'Driving Range' Really Matter? The Hidden Cost of Internal Combustion Engine Vehicles and the Potentially New Value Proposition of Electric Vehicles: Two Cases from Countryside and Urban Side of Japan[END_REF]

Australia

Conclusions

This discussion paper presented the recent advances in planning, modelling, evaluating city logistics for sustainable and liveable cities. We discussed these issues base on some applications in Europe, Japan, and Australia. There are two important factors promoting city logistics, the use of emerging technologies, including ICT, IoT, ITS, big data, AI, autonomous vehicles, robots, and the collaborations between stakeholders who are involved in city logistics. The emerging technologies help urban freight transport to be more efficient, environmentally friendly and less energy consumption, safer, and secured through the process of optimising the urban logistics networks, as well as integrating the logistics system. The integrated platform is essential for reducing the costs and environmental nuisance and providing new services.

The collaborations between stakeholders are critical for successful implementation of city logistics initiatives. As public entities and private companies are involved in city logistics, the Public-Private Partnerships (PPP) are essential for achieving the common goals of city logistics.

Data sharing between public sectors and private logistics companies are essential for identifying the issues and finding innovative solutions for urban freight and evaluating their effects in PPP.

Modelling city logistics using the simulation and optimisation techniques base on the emerging technologies is essential to anticipate the effects of policy measures and benefits for each stakeholder to make proper decisions.

Further research is needed in modelling urban freight transport in the dynamic domain for

  improving existing urban freight transport systems.We can collect precise data of movements of freight vehicles and goods using ITS and ICT. For example, GPS (Global Positioning Systems) and other tele-communication technology allows us to obtain location data of freight vehicles and goods at every second. Such historical data which are stored for a long term in computers can be used for optimising routing and scheduling of delivery in urban areas. On-line data are also important for dynamic operation of freight vehicles considering traffic congestion.Recently the IoT has become popular in production and logistics systems using sensors for measuring the location, acceleration and weight of loads of freight vehicles, the temperature within containers, as well as RFID (Radio Frequency Identification). The IoT can connect a great number of production sites, distribution centres, freight vehicles, and commodities. Networks based on ITS, ICT and IoT provide big data on urban freight transport systems. Mehmood et al. (2017) analysed the effects of big data on city transport providing a new understanding of load sharing and optimization in a smart city context. They demonstrated how big data can be used to improve transport efficiency and lower externalities in a smart city. Bibri (2018) highlighted IoT and related big data applications for smart sustainable cities, focusing on an analytical framework for data-centric applications enabled by the IoT to advance environmental sustainability. The important point of big data applications in city logistics is the collaborative operation of urban freight transport in sharing the capacity of vehicles, distribution centres and information systems in the sharing economy. Big data related to urban freight transport are typically owned by private companies but integration with public owned traffic and infrastructure data is needed for enhancing the operation of urban freight transport. Cleophas et al. (2019) discussed collaborative urban freight systems, identifying two key types of collaboration, vertical and horizontal. Vertical collaboration is referred to line-haul and last mile or multi-echelon distribution, whereas in horizontal collaboration partners serve the same or at least over-lapping parts of the transport network. They considered strategic, tactical, and operational planning horizons as well as different degrees of information exchange and planning centralization. Taniguchi et al. (2018a) presented concepts of an integrated platform for innovative city logistics with urban consolidation centres (UCC) and transhipment points (TP). The concepts encompass joint delivery systems with shared use of pickup-delivery trucks, urban consolidation centres and transhipment points based on big data analytics. These systems involve public-private partnerships among shippers, freight carriers, UCC operators, municipalities, and regional planning organisations, since the location of UCC and TP are highly related to urban land use plans and infrastructure provision as well as urban traffic management. ITS and ICT based communication systems for stakeholders are also essential for the efficient management of integrated platforms for both real-time and long-term operations.

  Autonomous vehicles are promising technologies which can provide efficient delivery services to city dwellers. Autonomous trucks or autonomous robots have been tested for last mile delivery of goods in urban areas. These innovative technologies may improve efficiency in terms of cost savings as well as reduce the negative environmental impacts. Delivery robots are also able to provide healthy distribution system with contactless service to customers in the COVID-19 pandemic times.[START_REF] Beirigo | Integrating people and freight transportation using shared autonomous vehicles with compartments[END_REF] studied modelling shared autonomous transportation of passengers and parcels for share-a-ride parcel locker problems in urban areas. They concluded that mixed purpose fleets for passengers and parcels performed on average 11% better than single-purpose fleets.[START_REF] Boysen | Scheduling last-mile deliveries with truck-based autonomous robots[END_REF] modelled the truck-based robot delivery-scheduling problem for last mile delivery. This problem aims to find an optimal truck route and a schedule for launching autonomous robots at a stop for delivering goods to customers by minimising the weighted number of late deliveries.Simoni et al. (2020) analysed robot-assisted last-mile delivery systems and pointed out that the truck-robot systems are quite efficient if robots are employed at heavily congested areas. Last-mile delivery robots allow contactless delivery to customers which can minimise the risk of infection at the time of COVID-19

Firdausiyah

  et al. (2019) presented multi-agent simulation models using adaptive dynamic programming which is a reinforcement learning method. In multi-agent models each agent learns to maximise the rewards which are given based on the decision of an agent. They applied these models in cases of urban goods delivery using urban consolidation centres (UCC) and concluded that adaptive dynamic programming method provided better performance than Q-learning in terms of profits of freight carriers and UCC operators in the cases of fluctuating demand of customers. The evaluation on the multiple criteria was done including reducing delivery costs and CO 2, NOx and SPM emissions. Rabe et al. (2018) applied a discrete event simulation to evaluate an UCC for distribution in Athens. They concluded that the simulation showed that utilizing UCCs lowered the number of tours needed to meet the customer's demands and decreased the required distance.[START_REF] Joubert | Evaluating the relocation of an urban container terminal[END_REF] applied the multi-agent transport simulation (MATSim) for evaluating the relocation of an urban container terminal in large scale scenarios in Cape Town, South Africa. Results showed that the simulation provided insights about how specific operators and the public at large will be influenced, both from an overall vehicle-kilometres travelled point of view and the change in travel times. Jlassi et al. (2017) evaluated the regulatory policies including the vehicle size and time windows in city logistics using a multi-agent simulation in Paris. They tested four scenarios and discussed the simulation results from various viewpoints of number of vehicles, emissions of CO2, NOx and SO2. Taniguchi et al. (2018b) demonstrated how multi-agent simulation can be used for evaluating a combination of city logistics policy measures focusing on consolidation centres,

  National and local governments try to encourage data sharing relating to urban freight transport. However, there are issues and barriers in executing practice. Moschovou et al. (2019) pointed out that the main barriers met in sharing freight data are legal barriers, resource barriers, competition barriers, and institutional barriers. Legal barriers mean the existence of laws that restrict data sharing. Resource barriers encompass the restrictions in funding and the lack of resources. Competition barriers are derived from the confidentiality of business in private companies. Institutional barriers indicate the limitation of sharing data between various organisations. In spite of these issues and barriers, some good examples of freight data sharing are observed in several countries in Europe, Japan and Australia, which are highlighted below.

Figure 3 . 1

 31 Figure 3.1 Data sharing scheme in Rotterdam (Source: City of Rotterdam)

Figure 3

 3 Figure 3.2 ETC2.0 Probe data collection in Japan (Source: MLIT)

Figure 3

 3 Figure 3.5 Basic Act on the advancement of public and private sector data utilization in Japan (2016) (Source: Cabinet Office)

  UK data sharing and information sharing is carried out within the Freight Quality Partnership for urban freight transport (Wainwright, 2020). For example, Central London Freight Quality Partnership (CLFQP) with Transport for London (TfL) and private sector organisations started in 2006 for central London. TfL executed Street space initiatives which aims at creating more space for people for safely walk, cycle, scoot, or wheel in response to the COVID-19 pandemic in 2020. Information on the change of road space usage, including street closure, footway made wider, restricted through traffic is shared with private companies, since this type of information is useful for smooth delivery of goods.

Figure 4 . 1

 41 Figure 4.1 Framework of integrated platform of city logistics

Figure 4 . 3

 43 Figure4.3 The interaction between stakeholders in city logistics[START_REF] Firdausiyah | Modeling City Logistics using Adaptive Dynamic Programming based Multi-Agent Simulation[END_REF]

Figure 4 . 5

 45 Figure 4.5 Experiments on autonomous vehicles for last mile delivery (Fujisawa city, Japan, Source: Yamato)

Figure 4 .

 4 Figure 4.7 shows an example of UCC in Tokyo for the multi-tenant buildings (MTB), Tokyo Sky Tree Town, which started in 2012. In this case three UCCs are set for delivering goods to the MTB where shops, restaurants, offices, schools, and aquarium are located. Multiple freight carriers drop off their goods at UCCs and a single freight carrier deliver goods to MTB and final destinations of shops, restaurants etc. within MTB. This freight carrier was involved in designing the goods distribution systems within MTB including the loading/unloading space, elevators, information systems from the beginning of planning MTB which was helpful for smooth and effective operations of logistics activities.

Figure 4 .

 4 Figure 4.8 illustrates the collaborations between stakeholders who are participating in the joint delivery systems with UCC. The developer (owner) of MTB is responsible for the good environment within and outside MTB and they financially support the joint delivery systems.As a result, the system achieved the lower UCC fee by 33-58% than other cases in Tokyo area, which freight carriers need to pay to the UCC operator. Note that the UCC operator is the same freight carrier who carry goods from UCC to MTB. The business model of supporting UCC is helpful for continuing the joint delivery systems. Tokyo metropolitan government gives advices on legal issues, although they do not provide subsidies.

Figure 4 .

 4 Figure 4.7 Multi-tenant building (Tokyo Sky Tree Town) and 3 UCCs in Tokyo[START_REF] Dupas | Towards optimising urban logistics with sustainable considerations in the city of Bordeaux, FFJ/Michelin workshop on city logistics for sustainable and liveable cities[END_REF]

Figure 4 . 9

 49 Figure 4.9 Reduction of number of trucks by the consolidation at UCCs to Tokyo Sky Tree Town[START_REF] Dupas | Towards optimising urban logistics with sustainable considerations in the city of Bordeaux, FFJ/Michelin workshop on city logistics for sustainable and liveable cities[END_REF]

Figure 4 .

 4 Figure 4.10 Location of three multi-tenant buildings, four UCCs and depots of freight carriers[START_REF] Dupas | A multi-commodity network flow model for sustainable performance evaluation in city logistics: Application to the distribution of multi-tenant buildings in Tokyo[END_REF]

  for the river Saine in Paris are used between the west port and the central Paris. The barges deliver cargo bikes with the parcels and pallets to the shops in central Paris and carry back electric waste on the way back. Automated delivery vehicles of follower robots and drones have been tested in 10 areas, for example Paris and Montpellier in France. They discuss the reliability and acceptability by citizens of automated delivery vehicles. Large scale multi-story logistics hotels were built in Paris and Lyon. These facilities are used for multi-purposes of logistics, retails, residential and offices. These were renovated from former industrial/rail areas or parking buildings. These facilities are located along with the peripheric road allowing the transhipment and inventory of goods. Small-scale logistics terminals in underground municipal car parks are also located in the city centre. Two types of facilities are effective for providing the connecting points of long-haul transport and the last mile delivery in the city centre. Cargo bikes are often used for the last mile delivery of short distances. Dupas, Deschamps, Taniguchi, Qureshi and Hsu (2021) presented innovative city logistics systems with UCC in Bordeaux. They assumed locations of five urban consolidation centres (UCC) in the peripheral area and three proximity logistics spaces (PLS) in the city centre. Two out of five UCCs and two out of three PLSs are operated in reality. Parcels are transported and consolidated in UCC and then delivered to PLS. From PLS to final customers cargo bikes are used for the distribution.

Duin ( 2021 )

 2021 presented recent development of city logistics in the Netherlands. He pointed out that there are initiatives for zero emission urban logistics in the city centres by 2025 in the Netherlands. However, the city logistics systems face the serious challenges for the near future, since the systems are very diverse and difficult to change. Some sustainable urban freight systems have been proposed such as: (a) Electrification (b) Smart city---smart loading/unloading (c) Consolidation principles---urban consolidation centres, city hubs, parcel boxes (Figure 4.19) (d) Smart concepts---sharing logistics, physical internet New booming is seen on the consolidation centres including the usage of moving mini hubs in the city where cargo bikes are used for the last mile delivery. Light electric freight vehicles (LEFV) are used in urban delivery and they can replace 10-15% of all the van trips. Experiences of LEFV revealed that spaces for transhipments, and law for identifying the type of vehicles and position on the roads are needed. Experimenting in the Living Lab with LEFV leads to adaptation, knowledge and mind change.

  privileges. Networks could be an important route. He presented examples from two networks, Gothenburg Freight Network "Godsnätverketi Göteborg" (GG) in Sweden and Central London Freight Quality Partnership (CLFQP) in UK. GG started in 2005, being driven by the transport planning authority with 25 participants for cooperation, discussion, communication, development of measures for better urban freight transport. CLFQP is the public and private sector organisation which started in 2006 with the partnership of Transport for London (TfL).

Thompson ( 2021 )

 2021 presented designing more efficient urban freight networks. He pointed out that the Improved vehicle loading, or the tonnes moved by km driven (tonne-km / vehicle-km ratio) is a key driver of emissions decrease in logistical field. This implies reducing the number of empty trips or km driven, increasing the use of available capacity in vehicles (which involves optimising three measures of capacity: volume, weight and space floor) and reducing the overall km driven by vehicles while delivering the same amount of goods. He discussed adapting Physical Internet (PI) principles for city logistics to transform the way physical objects are moved, stored, realized, supplied and used to improve efficiency and sustainability. The key elements of Physical Internet are open, integrated and shared networks, Standardised and modular load carriers, and Information Technology (Crainic and Montrueil, 2016). Thompson (2021) demonstrated case studies in Melbourne to show the shared pickup and delivery using parcel lockers and zero emission vehicles. It indicates the reduction of environmental costs by 75% and vehicle kilometres travelled by 50%.

  the real time operations of freight vehicles. Sharing resources between players in city logistics should be deeply investigated for innovative solutions. experiences. FFJ/Michelin workshop on city logistics for sustainable and liveable cities, Paris.Mehmood, R.,Meriton, R., Graham, G., Hennelly, P. and Kumar, M. (2017).Exploring the influence of big data on city transport operations: a Markovian approach, International Journal of Operations & Production Management, 37 (1), 75-104. Melo, S., Macedo, J., PatríciaBaptista, P. (2019). Capacity-sharing in logistics solutions: A new pathway towards sustainability, Transport Policy 73, 143-151. Moschovou, T., Vlahogianni, E. I. and Rentsiou, A. (2019). Challenges for data sharing in freight transport, Advances in Transportation Studies: an international Journal Section, B48, 141-152. Palacios-Argüello, L., Gonzalez-Feliu, J., Gondran, N., &Badeig, F. (2018). Assessing the economic and environmental impacts of urban food systems for public school canteens: case study of Great Lyon Region. European Transport Research Review, 10(2), 37. Rabe, M., Klueter, A. and Wuttke, A. (2018). Evaluating the consolidation of distribution flows using a discrete event supply chain simulation tool: Application to a case study in Greece, Proceedings of the IEEE 2018 Winter Simulation Conference. Scherr, Y. O., Saavedra, B. A. N., Hewitt, M. and Mattfeld, D. C. (2019). Service network design with mixed autonomous fleets, Transportation Research Part E, 124, 40-55. Simoni, M.D., Erhan Kutanoglu, E. and Claudel, C.G. (2020). Optimization and analysis of a robot-assisted last mile delivery system, Transportation Research Part E, 142, 102049. Taniguchi, E. (2020b). Data sharing between public sectors and private companies in Japan, Workshop on data sharing of public sectors and private companies for developing policies in city logistics, FFJ/EHESS, Paris. Taniguchi, E. (2021). Recent advances in city logistics based on emerging technologies and public-private collaborations, FFJ/Michelin workshop on city logistics for sustainable and liveable cities, Paris. Taniguchi, E. and Thompson, R. G. (2014). City Logistics: Mapping the future, CRC Press, New York. Taniguchi, E. and van der Heijden, R.E.C.M., (2000). An evaluation methodology for city logistics. Transport Reviews, 20(1), 65-90. Taniguchi, E., Dupas, R, Deschanmps, J-C. and Qureshi, A. G. (2018a). Concepts of an integrated Platform for Innovative City Logistics with Urban Consolidation Centers and Transshipment Points, In Taniguchi, E. and Thompson, R.G. (eds), City Logistics 3: Towards Sustainable and Liveable Cities, ISTE, London, 129-146. Taniguchi, E., Qureshi, A. G. and Konda, K. (2018b). Multi-agent simulation with reinforcement learning for evaluating a combination of City Logistics policy measures, In Taniguchi, E. and Thompson, R.G. (eds), City Logistics 2: Modelling and planning initiatives, ISTE, London, 165-178.Taniguchi, E.,Thompson, R. G., Yamada, T. and Duin, R. van (2001). City logistics -Network modelling and intelligent transport systems. Elsevier, Pergamon, Oxford.Taniguchi, E.,Thompson, R.G. and Qureshi, A.G. (2020a). Modelling city logistics using recent innovative technologies, Transportation Research Procedia, 46, 3-12. Thompson, R. G. (2020). Urban freight data sharing -Australian experiences, Workshop on data sharing of public sectors and private companies for developing policies in city logistics, FFJ/EHESS, Paris. Thompson, R.G. (2021) Designing more efficient urban freight networks, FFJ/Michelin workshop on city logistics for sustainable and liveable cities, Paris. Thompson, R.G., Nassir, N. and Frauenfelder, P. (2020). Shared freight networks in metropolitan areas, Transportation Research Procedia, 46, 204-211. Wainwright, I. (2020). Data sharing between public and private sectors, Workshop on data sharing of public sectors and private companies for developing policies in city logistics, FFJ/EHESS, Paris.

  presented sustainable solutions in urban and logistics management based on European experiences. He showed a good example of tenant led joint logistics in the shopping mall as well as shopkeeper led business model of Binnenstadservice Maastrich in the Netherlands. These good practices demonstrate successful application of joint delivery systems with UCC in Europe.

He discussed Low Emission Zone (LEZ), which stated for trucks in 2008, for vans in 2012, and cars in 2019 for keeping good air quality by controlling vehicles entering central London. From 2008, if entering the LEZ, all trucks with engines worse than Euro IV pay a charge of 100 or 200 £ per day. The impacts of LEZ for greater London and Ultra LEZ (ULEZ) for central London on the air quality in London was observed and the substantial reduction of PM10 can be seen. He showed the application of micro hubs for last mile delivery by cargo bikes and small electric vans, the use of waterways for supermarket retail logistics in Paris and London. He also highlighted the social benefits for city logistics solutions based on the TfL's FORS & Delivery & Servicing Plans in

London (2008London ( -2016))

, which depicts the substantial social benefits in terms of air quality and CO 2 emissions, infrastructure, noise, congestion, and accidents.

Acknowledgements

The author greatly acknowledges the generous support and assistance by FFJ/Michelin Foundation for the work. Special thanks go to Prof. Sébastien Lechevalier, Dr. Alexandre Faure of FFJ for their great help and suggestions to perform the research and the FFJ team for supporting workshops and other research activities at EHESS. He would like to express heartiest appreciations to the researchers in Europe and Australia for discussing city logistics in the online networking and workshops, including Prof. Laetitia Dablanc, Prof. Rémy Dupas, Prof. Jesus Gonzalez-Feliu, Assoc. Prof. Jean-Christophe Deschamps, Ms. Diana Dizian in France, Prof. Michael Browne in Sweden, Prof. Ron van Duin in the Netherlands, Dr. Jacques Leonardi in UK, and Assoc. Prof. Russell G. Thompson in Australia.

The author greatly acknowledges the generous support and assistance by FFJ/ Michelin Foundation for the work. Special thanks go to Prof. Sébastien Lechevalier, Dr. Alexandre Faure of FFJ for their great help and suggestions to perform the research and the FFJ team for supporting workshops and other research activities at EHESS.


Pascal Boyeldieu

Reflexes of a Labiovelar Series in Central Sudanic

INTRODUCTION

The Central Sudanic [CSD] languages are spoken in central Africa over parts of the D.R.C., Uganda, Sudan, C.A.R. and Chad. They comprise six subgroups of unequal size (representative languages are indicated in parentheses):

-[MMD] Moru-Madi (Moru, Avokaya, Logo, Lugbara, Ma'di), -[LND] Lendu (Ngiti, Lendu), -[MAS] Mangbetu(-Asua) (Asua, Mangbetu, Meje, Lombi), -[MEF] Mangbutu-Efe (Mangbutu, Ndo, Mamvu, Lese, Efe), -[KRS] Kresh (Kresh, Dongo, Aja ?), -[SBB] (Sara-)Bongo-Bagirmi (Modo, Baka, Bongo, Yulu, Gula dialects, Ndoka, Bagiro, Na, Kenga, Bagirmi, Sara languages). SBB is the most important subgroup in respect to both number of languages and geographical extension (see map).

While [START_REF] Tucker | The Non-Bantu Languages of North-Eastern Africa (with a Supplement on The Non-Bantu languages of Southern Africa by[END_REF][START_REF]Linguistic Analyses, The Non-Bantu Languages of North-Eastern Africa[END_REF] divided these languages in two different 'larger units' (Moru-Mangbetu vs Bongo-Bagirmi) despite their lexical and grammatical affinities, [START_REF] Greenberg | Languages of Africa[END_REF] grouped them together as the Central Sudanic branch of his Nilo-Saharan phylum.

Both [START_REF] Bender | Central Sudanic segmental and lexical reconstructions[END_REF] and [START_REF] Ehret | A Provisional Reconstruction of the consonants and vocabulary of Proto-Central-Sudanic[END_REF] tried to establish regular phonetic correspondences for these languages but in a rather unconvincing way. 1 The aim of this paper is to provide some evidence for correspondences involving articulations of the labiovelar type with the help of more recent data. 2

DOCUMENTATION AND COMPARATIVE SERIES

Despite gaps and unevenness in the documentation, most of the subgroups of Central Sudanic are relatively well documented by published data, for at least two languages (e.g. Mamvu and Lese for MEF). Nevertheless the documentation on the KRS languages is rather scanty and the position of Aja within the subgroup is uncertain. Therefore Kresh, Dongo and Aja forms will 1 To say things in a short way, Bender accepts more variations of sound and meaning than should be allowed in this kind of work. He namely identifies four series illustrating a CSD *kp formula: 71. *kpa 'big, long', 127. *kpa 'bone', 128. *kpa~gba 'hard' and 155. *ekpi 'cough' (his numbering) while only the second one seems to be relevant to me (see comparative series n° 2, 13, 14 and 15 below). Ehret (whose 1992 work has not been published) is not reliable as a whole, although he recognizes the *kw and *gw reflexes of MMD and may suggest some relevant cognations, like 'white' and 'moon' (see n° 25 below), for which I am indebted to him. Of course I took advantage of new data, published in the last decade. 2 I am very grateful to Raymond Boyd, Gerrit Dimmendaal, Robert McKee and Okoth Okombo for their reactions to a first draft of this paper. Some of their comments will be cited below.

be quoted as a reminder but they will neither be commented upon nor interpreted.

The data sources are indicated in Table 1 (see complete references at the end of this section). Note that [START_REF] Vorbichler | Neue Forschungsergebnisse zur phonologischen Analyse des Balese-Obi[END_REF] made some phonemic corrections for Lese (involving the frequent replacement of an original gß with qp) which are marked in the comparative series by (69).

For reasons of space, the SBB languages are illustrated as a whole by reconstructions cited from [START_REF] Boyeldieu | Identité tonale et filiation des langues sara-bongobaguirmiennes (Afrique centrale)[END_REF] and Boyeldieu, Nougayrol & Palayer (in preparation) (see the former for details of the consonant reflexes). The 'distribution level' ([1] to [5]) refers to the distribution of the lexical reflexes and probable antiquity of the SBB lexical series, [1] being the highest value.

Roughly speaking, CSD words seem to derive mainly from *VCV shapes (sometimes also *CV ?) which have become either CV or (C)VCV in the modern languages. Therefore the correspondence formulas concern consonants which, in most cases at least, were -and still are -intervocalic.

Table 2 displays the reflexes of four likely labiovelar correspondence formulas at the CSD level, *kp, *gb, *ngb and *Ñm, not only for modern languages but also for intermediate stages, defined as later levels which are historically common to each subgroup, MMD, LND, MAS, MEF and SBB.

The remaining tables show different comparative series (numbered from 1 to 35), most of which illustrate the correspondence formulas. Uncertain cognates are given in parentheses, followed by a '?'. As will be seen, some of these series seem to be relatively consistent with regard to vowels, while others are much more problematic, without even taking tones into account. Another problem is the fact that very few comparative series have clear cognates throughout all the subgroups; most of them show gaps. Consequently the identified formulas have to be regarded as working hypotheses rather than as accurate reconstructions, at least for the time being.

Although nothing sure can yet be said concerning vowels, it seems likely that the labiovelar formulas as a whole were, already at the CSD level, mainly followed by front or central vowels (like i, e, AE, a). Mergers or neutralizations respectively with *k, *g, *ng and *Ñ or *m may have occurred before back vowels at an earlier time. Similar tendencies could also justify some cases of osculation, where labiovelars seem to alternate, in an irregular way, with other consonants in the same series (see *kp/*k in 8 and 11, *gb/*g in 19-21, *Ñm/*m in 33).

REFLEXES OF *kp

The best series illustrating a CSD *kp formula are 1.clean, 2.bone, 3.man, male, 4.play/game/song, 7.tree, 8.bowels and 9.seed, grain.

In MMD, reflexes of *kp are kw/tsw (before a/AE~i) in Miza and Moruägi, hw/kw (before a/AE~i) in Ug. Ma'di and f in all other languages. The most likely form of a common reconstruction at the MMD level is *kw.

In LND, the reflexes are kp (series 1-4, 6) in all languages but apparently also ts, if the forms cited in the series 7-9 are reliable cognates (note that parallel reflexes of dz and nz~ndz also occurr in the cases of *gb and *ngb, see below). The conditioning of these variants is unclear. It may have been of a vocalic nature (alveolar affricates before front or high vowels? see the situation in Miza and Moru-ägi above) but then it must have occurred at an earlier stage, prior to vowel changes, since the current vowels observed after ts (and dz, nz~ndz) are not quite consistent with this explanation. In any case, the common formulas at the LND level have to be reconstructed as *kp and *ts respectively.

The reflexes of CSD *kp are less obvious in MAS. I suggest that the kp's occurring throughout MAS in series 2.bone are not instances of regular reflexes; these should rather be sought from other series, none of which is complete for this subgroup. However, series 12.hen, though limited to MAS only, gives a full set of the likely reflexes which are kw in Aka, Asua and Lombi D, xw (/h before o?) in Lombi L and w/ø (ø before a under certain conditions?) in Mangbetu. Therefore the common reconstruction at the MAS level has to be characterized as *kw.

In MEF, the reflexes are clearly Mamvu f and Lese gß (qp 69),3 which can probably be reconstructed as a common *kp at the MEF level. 4Finally the SBB common reconstruction is *kp, whose reflexes are kp, k, t, p or ø (sometimes with compensatory nasalization of the vowel) in the modern languages.

CSD *kp alternates with *k in series 8 and 11.

As is the case for MAS in series 2 (see above), series 13-15, which I consider irregular, show different occurrences of kp both in MMD and in MAS (maybe also qß in MEF, see series 15?) but I suggest that these kp, although they do belong to the phonological systems of the languages, are not historical reflexes of the CSD formula *kp.

REFLEXES OF *gb

The evidence for a CSD *gb formula, mainly provided by the series 16-17 (and 20?), is less obvious and some of its reflexes are unclear.

MMD has reflexes parallel to those of *kp, namely Miza dzw/d©w and Moru-ägi dz/d© (both before AE/i), Ug. Ma'di, Lokai and Lulu'ba gw, other languages v. It is unclear whether the instances of g before u (all languages) occurring in series 20 have to be regarded as a reflex of *gb in this vocalic context or as a result of a *gb/*g osculation. The common MMD reflex may be given as *gw.

LND has parallel reflexes which are gb (series 16, 20-21) and most probably dz (series 17, 19) for all languages. Consequently the LND common reconstructions are *gb and *dz.

In MAS, Asua D, Mangbetu and Lombi D (other languages are not documented) usually show g (series 16-17, 19, 21) but again it is not clear whether these g's are reflexes of *gb or a result of CSD *gb/*g osculations, such as the ones observable at least in SBB in series 19 and 21.

The MEF situation is unclear and insufficiently documented: series 16 gives Mamvu g and Lese gß (kp 69), but series 19 gives g (< *g?) for both languages.

SBB as a whole has a *gb reconstruction (16-17, 20) but shows osculations with *g in 19 and 21. Modern languages have gb, g, d or b as reflexes of *gb.

Finally, I consider series 22-23 as irregular, as Mangbetu and MMD gb are not historical reflexes of CSD *gb (in both series, the reflexes of SBB *gb are themselves irregular).

REFLEXES OF *ngb

The CSD formula *ngb is somewhat better documented by series 23-26. MMD reflexes, parallel to those of *kp and *gb, appear as Ñgw/ nd©w~ndzw (before a/AE) in Miza and Moru-ägi, Ñgw in Ug. Ma'di, Lokai and Lulu'ba, and mv elsewhere. The common reflex for MMD is characterized as *ngw.

The LND languages again have either ngb or nz~ndz, both reflexes appearing in the sg. and pl. forms respectively of series 24.child. LND reconstructions are given as *ngb and *ndz.

In MAS, all languages have ngw~Ñgw (before a and AE, 24-25) and ng(w) (before o, 26), which can be reconstructed as MAS *ngw.

For MEF, series 24-26 show Mamvu ng (before back vowels) and Lese gb. 5 Mamvu ngb (series 28) might be understood as a complementary variant of ng before a but uncertain cognates in series 27 and 29 are not consistent with this idea. Therefore the characterization of a common MEF reconstruction as *ngb is tentative.

The only clear instance of SBB *ngb appears as an uncertain cognate in series 27, so that reflexes of CSD *ngb in this subgroup, though probable, are not firmly established (SBB reflexes of *ngb are ngb~Ñb, ng, nd or mb).

Finally, series 29-30, which I consider irregular, show some instances of MMD mgb~Ñgb (MMD *ngb?) which are not historical reflexes of CSD *ngb.

REFLEXES OF *Ñm

Though scanty and deficient, series 31-33 seem to offer some evidence of a CSD *Ñm formula.

In MMD (see also [34][35], reflexes are Ñ(w) in most languages and ny~ñ in Keliko (but 35 Ñ), Lugbara, Lugbara C and Ug. Ma'di. The instances of m before u (series 32) could be regarded as variant reflexes of MMD *Ñw in this particular vocalic context.

The available reflexes in LND are usually m, except for Ddradha, which has Ñ (series 33), thus strongly suggesting *Ñm as a common LND reconstruction.

In MAS, Asua D and Mangbetu mu~mw and Lombi D Ñw are illustrated by the same incomplete series and suggest a common MAS reconstruction *Ñw. Robert McKee (pers. comm.) very kindly completed these data for a subdialect of Meegye (or Meje), another MAS language, with nÓÑ w À ñÓm w À 'fly-whisk' and nÓÑ w à ~ nÓm w à 'spoil, rot (intr.)', which emphasize the phonetic affinities and alternations between [Ñ w ] and [m w ].

There are no available MEF data concerning possible reflexes of CSD *Ñm.

Finally How should we characterize these formulas at the CSD level? In other words, which is the most likely source, [kp] or [kw], for both labialized velar stops and labial-velar stops? There seem to be two kinds of approach to this question.

The first one is of an articulatory nature. Okoth Okombo (pers. comm.) argues that the coarticulations of kp, which do not share any common feature (k 'velar', p 'labial'), are "not so peaceful (more marked)" while the ones of kw, which do share a common feature (k 'velar', w 'labial+velar'), are "a bit more peaceful (less marked)". The change kp > kw seems to him more likely than kw > kp and he therefore suggests a *kp proto-form.

The second approach is of a more areal-comparative and historicalsociolinguistic nature. Commenting on some areal features of African languages, Greenberg (1983: 8) claims that "[...] coarticulated labiovelars [i.e. sounds of the kp type] are basically a Niger-Congo feature" and he later suggests that "from Niger-Congo these sounds spread at an early date to Central Sudanic in the Nilo-Saharan family probably from Adamawa-Eastern". This is also the opinion of Gerrit Dimmendaal (pers. comm.), who argues that "hardening processes of this type [i.e. *kw > kp, *gw > gb and *Ñw > *Ñm] are also attested in Eastern Nilotic languages belonging to the Bari group as well as Western Nilotic Alur. [... labial-velars...] emerged in these Nilotic languages under strong influence (and bilingualism) with neighbouring Central Sudanic languages". He finally suggests that similar changes may have occurred within Central Sudanic through contact with Adamawa-Ubangi.

I agree with the idea that Central Sudanic labial-velar stops may have originated in contact with (pre-)Adamawa-Ubangi languages but, if so, I would claim that this change occurred, as Greenberg says, "at an early date" (my emphasis). Greenberg also states that "the sounds under discussion are surely not to be posited for proto-Nilo-Saharan although they may well be proto-Central Sudanic". Indeed I find it hard to reconcile the hypothesis of relatively recent, individual changes from a CSD *kw to *kp in any subgroup with the fact that the MMD and MAS languages, which are closer to neighbouring Ubangi languages (Mundu, Zande, Mayogo, Mba), have *kw reflexes while LND, which is not in contact with Ubangi, has *kp reflexes. It seems to me more likely that the common Central Sudanic system already had labial-velar stops (*kp etc.), which then 'softened' to labialized velar stops (*kw) in MMD and in MAS. Both subgroups nevertheless show instances of labial-velar stops which are not reflexes of the common formulas and may be due to lexical rebuildings or innovations.

CONCLUSION

Despite the gaps in most comparative series and the unsolved problems involving vowels, there seem to be some solid arguments in favor of reconstructing labiovelars from cognates in MMD, LND, MAS, MEF and SBB, thus supporting the historical unity of these subgroups at a CSD level.

However instances of labial-velar stops in the modern languages do not necessarily represent reflexes of the CSD formulas *kp, *gb, *ngb and *Ñm, which may have given labialized velars, labial fricatives or alveolar affricates according to language and phonemic environment.

Lastly the characterization of these formulas as labial-velar rather than labialized velar stops seems to me the best way to account for the nature and distribution of their current reflexes.

Moru-ändri ((C)V)CV f v , (g-u ?) mv Ñw-a, m-u Ojila ((C)V)CV f v , (g-u ?) mv Avokaya V ((C)V)CV f v , (g-u ?) mv Ñ-a, m-u Logo ((C)V)CV f v , (g-u ?) mv Ñw-a, m-u Logo V ((C)V)CV f v , (g-u ?) mv ? , m-u Keliko ((C)V)CV f v , (g-u ?) mv ? , ny-u Lugbara ((C)V)CV f v , (g-u ?) mv ny Lugbara C ((C)V)CV f v , (g-u ?) mv ñ Ug. Ma'di ((C)V)CV hw-a,

kp, *gb, *ngb ans *Ñm respectively

  SBB has *Ñm (31), partially alternating with *ng (32), but *m everywhere in (33), indicating an *Ñm/*m osculation at the CSD level. Reflexes of SBB *Ñm in modern languages are Ñm, Ñ, m or w) . . Yet the question of the exact phonetic nature of these consonant formulas remains open. It has been shown that they may be identified, at intermediate levels, either as labialized velar stops (*kw, *gw, etc.) or as doubly articulated labial-velar stops (*kp, *gb, etc.) according to the different subgroups. 6 Reflexes show a remarkable parallelism in the sense that MMD and MAS are throughout characterized with articulations of the first type, while LND, MEF and SBB show articulations of the second type. Subgroup formulas are summarized in the following table:

	7. THE PHONETIC NATURE OF CSD LABIOVELARS
	CSD labiovelar formulas have thus far been characterized as *CSD *kp ~ *kw ? *gb ~ *gw ? *ngb ~ *ngw ? *Ñm ~ *Ñw ?
	MMD	*kw	*gw	*ngw	*Ñw
	LND	*kp / *ts	*gb / *dz	*ngb / *ndz	*Ñm
	MAS	*kw	(*g ?)	*ngw	*Ñw
	MEF	*kp	*?	*ngb ?
	SBB	*kp	*gb	(*ngb ?)	*Ñm

Table 1 .

 1 Language grouping and sources

	CSD	CENTRAL SUDANIC
	MMD	Moru-Madi
	Miza	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Moru-ägi	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Moru-ändri	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Ojila	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Avokaya V	Vallaeys 1986
	Logo	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Logo V	Vallaeys 1986
	Keliko	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Lugbara	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Lugbara C	Crazzolara 1960
	Ugandan Ma'di	Boone & Watson 1996-98 (BW)
	Lokai	Tucker 1940 / Boone & Watson 1996-98 (BW)
	Lulu'ba	Tucker 1940 / Boone & Watson 1996-98 (BW)
	LND	Lendu
	Ngiti	Kutsch Lojenga 1994
	Djadha	Kutsch Lojenga 1994
	Lendu D	Dhejju 1978
	Ddradha	Kutsch Lojenga 1994
	MAS	Mangbetu(-Asua)
	Aka	Larochette 1958
	Asua L	Larochette 1958
	Asua D	Demolin 1992
	Mangbetu L	Larochette 1958
	Mangbetu D	Demolin 1992
	Lombi L	Larochette 1958
	Lombi D	Demolin 1992
	MEF	Mangbutu-Efe
	Mamvu	Vorbichler 1971
	Lese	Vorbichler 1965, 1969
	KRS	Kresh
	Kreish B	Boyd (n.d.)
	Kreish S	Santandrea 1976
	Dongo	Santandrea 1976
	Aja	Santandrea 1976
	SBB	(Sara-)Bongo-Bagirmi
		Boyeldieu 2000 / Boyeldieu, Nougayrol & Palayer (in preparation)

Vorbichler (1969: 144) distinguishes three voiceless back phonemes for Lese, namely /kp/ ('voiceless explosive', for which he cites

instances), /qß/ ('voiceless labio-postvelar implosive', 4 instances) and /qp/ ('voiceless labio-postvelar explosive', 6 instances). Do they really contrast in the language? 4 Note that MEF is characterized on the basis of Mamvu and Lese only, two closely related languages. It could be revised if one considered other languages like Mangbutu and Ndo, for which I could not find available data.

The correspondences of Mamvu prenasalized voiced obstruents with Lese plain voiced obstruents are regular and well attested.

These articulatory definitions are taken from[START_REF] Ladefoged | The Sounds of the World's Languages[END_REF]

Compare 2.bone and 3.man, male? Mamvu/Lese: 'gross, gewaltig'.

Avokaya V/Logo V: a. 'brûler, faire bouillir', b. 'bouillir'; Mangbetu L: 'être malade, bouillir'.

 16 Ngiti: a. 'to be forgotten', b. 'to forget'; Mangbetu L: a. 'oublier, perdre', b. 'plonger, se perdre, disparaître'.

Ngiti/Lendu D: 'pinch/pincer'; Mangbetu D: a. 'se gratter', b. 'égratigner'; Mamvu/Lese: 'ausgraben, scharren'.

Avokaya V/Logo V: 'cour, plaine; dehors, dans la cour'.

Logbara: 'to beat, strike'; Lese: a. 'stecken bleiben, anstossen', b. 'an/gegen etwas stossen, anstossen, dagegenstossen'.


Maxim Germer
email: maxim.germer@tu-dresden.de

Uwe Marschner

Andreas Richter

High Efficient Boost Energizing and Transferring Circuit for Electromagnetic Energy Harvesting

Interface circuits play an important role within the energy harvesting transduction chain. Sophisticated circuits allow extracting energy efficiently and provide output voltages significantly higher than standard techniques would allow. In this work, an easy and highly efficient interface circuit for electromagnetic energy harvesting (EMEH) is presented. As the EMEH open electric circuit voltage is typically low, this circuit aims at charging a capacitor to a higher voltage efficiently. A switch short-circuits and opens the transducer periodically to energize and transfer the energy to the capacitor. Based on unidirectionally coupled differential system equations, the energy efficiency is analyzed for both the discontinuous conduction mode (DCM) and the continuous conduction mode (CCM). The problem solution reveals a general description of the optimal ratio between short-circuit and open circuit for any linear electromagnetic energy harvester. It enables to set up the interface circuit properties, solely based on the electromagnetic system properties and based on the energy storage.

I. INTRODUCTION

Electromagnetic energy harvesting (EMEH) is one of few main methods to transduce vibrational energy into electrical energy. The change of a magnetic field with respect to a coil, induces a voltage at the terminals of the coil. Coupled differential equations are used to describe the interaction between mechanical and electrical domain, whereas the electrical circuit representation consists in a series connection of a controlled voltage source, a resistance and an inductance. To use the provided energy for many shock driven applications, a temporary storage like a capacitor is required [START_REF] Germer | ASME 2020 Conference on SMASIS[END_REF]. Generally, small-scaled electromagnetic energy harvesters provide a much smaller output voltage compared to their piezoelectric counterparts. Additionally, rectifying diodes cause significant losses during the electrical energy extraction, which is why active fullwave rectifiers and active voltage doublers have been studied to reduce these losses [START_REF] Rao | [END_REF][START_REF] Ulusan | Transducers & Eurosensors[END_REF]. However, the capacitor voltage represents a second voltage barrier and influences the energy transfer. Step-up converters relativize the voltage drop and allow to charge the storage to a higher voltage than the induced voltage. Arroyo et al. [START_REF] Arroyo | Sensors and Actuators A: Physical[END_REF] and Sanchez et al. [5] presented a promising circuit concept. They used the analogy of electric charge and magnetic flux and presented a synchronized magnetic flux extraction circuit, extracting the electrical energy load independently. The terminals of the EMEH are kept short circuited to obtain a maximum magnetic field in the inductor, equivalent to a maximum current. When this field maximum is reached, the connection is opened and the energy of the inductor is transferred to the electrical load. The next cycle starts, when the polarity of the current has changed. Own calculations for unidirectionally coupled EMEHs have shown, that the circuit efficiency can be increased up to 79.5%. However, efficiency optimization is challenging, as ideal inductors, being very large in size, are required. Real inductors with resistive part significantly decrease the efficiency to only a few percent. Additionally, compared to a piezoelectric synchronous charge extraction circuit, the inductance of an EMEH has no memory and do not accumulate the magnetic field energy, whereas the piezoelectric capacitance accumulates the charges and a circuit efficiency of up to 100% can be reached, theoretically.

II. INTERFACE CIRCUIT AND ENERGY ESTIMATION

This circumstance leads to a new, easily implementable boost interface circuit, using solely the intrinsically inductance of the EMEH as element to be energized and to transfer the energy, while being short-circuited and opened multiple times within one oscillation, respectively. The circuit is depicted in FIG. 1, whereas u(t), L, R and are the induced voltage, the inductance and the resistance of the EMEH, respectively.

FIGURE 1: Electromagnetic energy with interface circuit

The switch sets the inductance energizing time 𝑡 E and the transferring time 𝑡 T . When the switch is closed, a RL-network is formed. As the current 𝑖 is limited by 𝑖 0 = 𝑢 0 /𝑅 and as the inductance causes a phase shift, the current raise is high at the beginning of the inductor charging phase, e.g. 𝑖(𝜏) -𝑖(0) = 0.63 𝑖 0 whereas 𝑖(4𝜏) -𝑖(3𝜏) = 0.03 𝑖 0 , whereas 𝜏 = 𝐿/𝑅. On the hand, the longer the switch is closed, the higher both the current 𝑖 and the energy 𝐸 = 𝐿𝑖 2 /2 are. On the other hand, the inductance could have been discharged and recharged multiples times n during the same time T, leading to a higher total energy E. To find the best ratio 𝑡 E /𝜏 as well as 𝑡 T /𝜏, if the transferring time is non-negligible, the following conditions are assumed. (1) Weakly coupled systems: the electrical domain has almost no influence on the mechanical domain, (2) the coil resistance is dominating the source impedance: 𝜔𝐿 ≪ 𝑅, (3) Quasistatic oscillation (𝑇 ≪ 𝜏): the oscillation period T is much larger than both energizing and transferring time, depending both on 𝜏.

A. Full transfer mode (FTM)

Let 𝑢(𝑡) = 𝑢 0 be the voltage source of the electrical circuit branch, which can be considered constant due to assumption (3). A switch short circuits and opens the EMEH periodically after 𝑡 E and after 𝑡 E + 𝑡 T , respectively. The transferring time is chosen, such that the inductor energy is fully transferred. The total energy that can be extracted is the sum of each charged inductance energy:

E = ∑ 𝐿 2 𝑖 𝐹𝑇𝑀 2 (𝑡 = 𝑝 ⋅ 𝑡 E ) 𝑘 𝑝=1 ,
whereas the p th inductance current 𝑖 FTM is given by

𝑖 FTM (t) = 𝑖 0 (1 -exp (- 𝑡 E 𝜏
)) and 𝑖 0 = 𝑢 0 𝑅 .

Consequently, the accumulated inductor energy is

E FTM = k ⋅ 𝐿 2 𝑖 0 2 (1 -exp (- 𝑡 E 𝜏 )) 2 .
During the time 𝑡 T , the energy is transferred. Within a given time 𝑇, the inductor can be charged and discharged 𝑘 times, whereas 𝑘 = 𝑇/(𝑡 E + 𝑡 T ). Replacing 𝑘 leads to the expression of the energy

E FTM = T 𝑡 E + 𝑡 T ⋅ 𝐿 2 𝑖 0 2 (1 -exp (- 𝑡 E 𝜏 )) 2 .
The normalization to the maximal attainable energy 𝐸 0 = 𝑇𝑅𝑖 0 2 /4 during T under load matching and substitution of 𝑥 = 𝑡 E /𝜏 and 𝑚 = 𝑡 T /𝜏 leads to the expression of the efficiency

𝜂 𝐹𝑇𝑀 = 2 ⋅
(1 -exp(-𝑥)) 2 𝑥 + 𝑚 .

Setting the derivative of 𝜂 with respect to 𝑥 to zero and the derivative of 𝜂 with respect to 𝑚 to zero leads to a system of equations, whose solution is described by exp(𝑥 𝑚 ) -2𝑥 𝑚 -1 -2𝑚 = 0. The pairs (m, 𝑥 𝑚 ), maximizes the efficiency, which is illustrated in FIG. 3 as function of 𝑚. As a result, the efficiency is limited by 80 % and necessitates the switch opening periodically at 𝑥 = 𝑡 E /𝜏 = 1.25 and 𝑚 = 𝑡 T /𝜏 = 0 (immediate energy transfer). Even if the maximal efficiency is equivalent to the one of a perfect SFME, no ideal and bulky tuning inductor is necessary. Further, no complex algorithm such as maximum peak detection or zero crossing detection have to be embedded. A switch with defined energize and transfering times is enough to obtain high load independent energy efficiencies and is able to increases a storage capacitor voltage as load to a higher voltages than the electromagnetic output voltage. Under realistic conditions (m>0), overall efficiencies of >60% can be reached, easily.

B. Partial transfer mode (PTM)

Even higher efficiencies can be obtained, if the inductance is not entirely discharged, but if it maintains a current 𝑖 L0 , leading to the partial transfer mode (PT). The current is calculated by

i PTM (t) = i 0 (1 -exp (- 𝑡 E 𝜏 )) + 𝑖 L0
and the added energy is expressed as

E PTM = k ⋅ 𝐿 2 (𝑖 0 2 (1 -exp(-𝑥)) 2 -𝑖 L0 2 ),
Substituting 𝑛 = 𝑖 𝐿0 /𝑖 0 and normalization to 𝐸 0 results in the expression of the efficiency 𝜂 𝑃𝑇𝑀 = 2 ⋅ 𝑛 2 (e -2x -1) -(e -x -1)((2𝑛 + 1)𝑒 -𝑥 -1) 𝑥 + 𝑚 .

Similar to the FTM, the efficiency is derived according to x, 𝑛 and 𝑚, respectively, and the derivatives are set to 0. The solution of the system of equations is described by sinh(𝑥 𝑚 ) -𝑥 𝑚 -𝑚 = 0 𝑛 𝑚 = (1 + exp(𝑥 𝑚 )) -1 . The maximal efficiency as function of 𝑚 is illustrated in Fig. 3.

FIGURE 3: Optimal energy efficiency as function of relative transferring time m for PTM and FTM

For the triple (𝑚, 𝑥 𝑧 , 𝑛 𝑧 )=(0,0,1/2), an efficiency of 100% is reached. While m can be very small in practice, a time ratio x = 0 is not physically meaningful to charge the inductor. Only in theory, the FTM leads to an efficiency increase compared to the PTM. However, a FTM based circuit needs much more functionality to maintain a minimal current 𝑖 L0 . In practice, the objective is to charge a capacitor. As the time to transfer all the inductor energy decreases with the capacitor voltage and is limited by 𝑡 𝑇 ≤ √𝐿𝐶/4, the presented circuit with fixed times 𝑡 E and 𝑡 T is a combination of both methods FTM and PTM.

III. CONCLUSION

The study presented two new concepts to transfer electrical energy efficiently from an electromagnetic energy harvester (EMEH) towards a storage. Both concepts periodically shortcircuit and open the EMEH periodically. Analytical calculations have revealed that efficiencies of 80% and 100% are possible for the FTM and PTM, respectively. Due to the simplicity of the FTM circuit, its application is preferable and provides higher voltages than the output of the electromagnetic transducer.

  FIGURE 2 presents the current evolution of the inductance and the amount of totally transferred energy, being charged during 𝑡 E and entirely transferred during 𝑡 T , here 𝑡 T = 0, once, twice and fourth.

FIGURE 2 :

 2 FIGURE 2: Inductor current and transferred energy for different energizing times 𝑡 E /𝜏 and 𝑡 T /𝜏 = 0

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Lucie Barateau

Régis Lopez

Sofiene Chenini

Anna-Laura Rassu

Sabine Scholz

Manuela Lotierzo

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Association of CSF Orexin-A levels and nocturnal sleep stability in patients with hypersomnolence

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