A model based DC analysis of SiPM breakdown voltages

A new method to determine the breakdown voltage of SiPMs is presented. It is backed up by a DC model which describes the breakdown phenomenon by distinct avalanche turn-on ($V_{01}$) and turn off ($V_{10}$) voltages. It is shown that $V_{01}$ is related to the 'breakdown voltage' that previous DC methods derive from simple reverse current-voltage measurements, while $V_{10}$ is the 'real' breakdown voltage commonly obtained from complex gain-voltage measurements. The proposed method reveals how the microcell population distributes around $V_{01}$ and $V_{10}$. It is found that if this distribution is assumed to be normal, then both voltages and even their standard deviation can readily be extracted from current-voltage curves. Measurements are in good agreement with the theoretical model

Optimal auctions with externalities and signaling

This paper asks how to design a revenue-maximizing auction in the presence of post-auction market competition and asymmetric information. In this situation, bidders, depending on the auction mechanism, can signal their type through their bidding behavior which influences the outcome of the post-auction market game. Thus the auctioneer has to design a mechanism that not only specifies who wins the good but also describes the amount of information that can be revealed about the winer through signaling. This paper shows that to reveal all information about the winner can be optimal under some conditions.

Spin state dependence of electrical conductivity of spin crossover materials

We studied the spin state dependence of the electrical conductivity of the spin crossover compound [Fe(Htrz)2(trz)](BF4) (Htrz = 1H-1,2,4-triazole) by means of dc electrical measurements. The low spin state is characterized by higher conductance and lower thermal activation energy of the conductivity, when compared to the high spin state

Connected Cruise and Traffic Control for Pairs of Connected Automated Vehicles

This paper considers mixed traffic consisting of connected automated vehicles equipped with vehicle-to-everything (V2X) connectivity and human-driven vehicles. A control strategy is proposed for communicating pairs of connected automated vehicles, where the two vehicles regulate their longitudinal motion by responding to each other, and, at the same time, stabilize the human-driven traffic between them. Stability analysis is conducted to find stabilizing controllers, and simulations are used to show the efficacy of the proposed approach. The impact of the penetration of connectivity and automation on the string stability of traffic is quantified. It is shown that, even with moderate penetration, connected automated vehicle pairs executing the proposed controllers achieve significant benefits compared to when these vehicles are disconnected and controlled independently.Comment: Accepted to the IEEE Transactions on Intelligent Transportation Systems. 11 pages, 10 figure

The development and application of impact evaluation and project formulation methods in capacity building of food control systems in developing countries

La sécurité sanitaire des aliments est un défi majeur pour de nombreux pays, qui restreint leur accès au plein potentiel économique et social qu'ils pourraient avoir. La bonne marche et la performance de haut niveau des systèmes de contrôle des aliments dans les pays développés sont le fruit de décennies d'investissements de l'ordre de milliards de dollars dans le renforcement des infrastructures et des capacités des acteurs de la sécurité sanitaire des aliments. Les pays en développement ne peuvent se permettre un processus aussi coûteux et un progrès aussi lent dans la construction de leurs systèmes de contrôle des aliments, en raison des innombrables conséquences négatives pouvant affecter la santé publique et le manque à gagner potentiel du secteur de production alimentaire et agro-alimentaire, souvent considéré comme secteur vital d'économies émergentes comme celles de ces pays, notamment du fait de sa contribution aux exportations et donc à la balance commerciale. Malgré le fait qu'une grande partie de l'aide internationale est acheminée vers l'amélioration des capacités et des pratiques en matière de sécurité sanitaire des aliments dans ces pays, les résultats sur le terrain restent peu visibles, et rarement durables, notamment en ce qui a trait à la performance des programmes règlementaires qui sous-tendent les systèmes de production alimentaire de ces pays. L'étude des conditions d'amélioration et d'optimisation de l'efficacité des investissements en matière de renforcement des capacités en sécurité sanitaire des aliments dans les pays en développement n'implique pas seulement la nécessité de définir de meilleures directives sur la formulation des projets et l'évaluation de l'impact, mais doit passer par l'élaboration de nouvelles approches, notamment des approches décisionnelles ancrées dans l'analyse de données factuelles du terrain, afin d'identifier et de définir les contours des investissements nécessaires. Pour relever ce défi, ce travail a procédé à une revue critique des approches et outils actuels appliqués par les agences de développement, actives dans le domaine de la sécurité sanitaire des aliments. Cette revue a permis l'identification de critères de succès et des bonnes pratiques appliquées au sein de ces organisations, notamment en matière de gouvernance et de gestion des activités de renforcement des capacités en sécurité sanitaire des aliments. Une étude comparative a suivi deux pays sélectionnés sur la base de critères définis : le Pakistan et le Viet Nam, en analysant les approches d'investissement dans le renforcement de la sécurité sanitaire des aliments et leurs retombées dans chacun de ces pays. Les leçons apprises et les recommandations tirées de ces analyses ont été mises à profit dans le développement et la proposition de nouveaux outils et directives à appliquer dans les initiatives de renforcement de capacités en sécurité sanitaire des aliments, tout au long du cycle de vie de ces initiatives. Enfin, ce travail a conduit à l'élaboration d'une approche ancrée dans l'analyse des données pour guider le processus décisionnel de la conception, de la mise en œuvre et de la surveillance de projets de renforcement de la sécurité sanitaire des aliments. Cette approche tient également compte des sections pertinentes des directives du Codex Alimentarius et d'autres retombées de recherches associées à la prise de décision dans les politiques publiques, fondées sur l'analyse de données. Il est attendu que la nouvelle approche proposée par cette recherche ouvre des perspectives nouvelles vers une meilleure efficacité et efficience des investissements actuels et futurs en matière de renforcement des capacités en sécurité sanitaire des aliments.Food safety remains a challenge for many countries, limiting their ability to maximize the economic and social potential and attain their objectives of human and economic development. The high-level performance of robust food control systems in developed nations has resulted from decades of experience and billions of dollars' investments in building infrastructures and capacities of food safety stakeholders. Developing countries cannot afford such a costly and lengthy process due to the negative consequences of unsafe food affecting their public health and agri-food trade. Although a large sum of international aid is being channeled towards the upgrade of food safety capacities and practices in these countries, results on the ground can often be invisible and struggle with sustainability issues, particularly for enhancing the performance of food control systems. Investigating the possibility of improving the "value for money" of these investments in developing countries entails setting better guidelines on project formulation, impact assessment and approaches in food regulatory decision-making. As outlined in this research, the latter can be further explored by better using data for the evidence-based identification of required capacity building investments and their prioritization. This research examines and recommends an integrated approach with short- and long-term solutions to achieve such a goal. It also offers a review of current technical methods and strategies followed by development agencies active in food safety and identifies current best practices applied by such agencies, especially related to food safety capacity building. This research relies on a comparative analysis of food safety capacity building programs targeting two countries, namely Viet Nam and Pakistan, selected based upon defined criteria. The lessons learned and recommendations gained from these analyses were used to develop a new set of proposed guidelines for project formulation, implementation, and evaluation. Development agencies and competent authorities could adopt these guidelines to improve their capacity building practices. As a long-term solution for identifying capacity building needs and performance assessment of food control systems, a data-driven food regulatory decision-making approach was discussed as a possible way forward for regulators. This system was structured based on the relevant sections of Codex guidelines and other research, focusing on using data for public services. It is expected that the application of the recommendations stemming from this research will help shape a new way for food safety capacity development, improving the efficiency and effectiveness of investments in this area, with a potentially positive impact on other development areas

Temperature, but Not Available Energy, Affects the Expression of a Sexually Selected Ultraviolet (UV) Colour Trait in Male European Green Lizards

Background Colour signals are widely used in intraspecific communication and often linked to individual fitness. The development of some pigment-based (e.g. carotenoids) colours is often environment-dependent and costly for the signaller, however, for structural colours (e.g. ultraviolet [UV]) this topic is poorly understood, especially in terrestrial ectothermic vertebrates. Methodology/Principal Findings In a factorial experiment, we studied how available energy and time at elevated body temperature affects the annual expression of the nuptial throat colour patch in male European green lizards (Lacerta viridis) after hibernation and before mating season. In this species, there is a female preference for males with high throat UV reflectance, and males with high UV reflectance are more likely to win fights. We found that (i) while food shortage decreased lizards' body condition, it did not affect colour development, and (ii) the available time for maintaining high body temperature affected the development of UV colour without affecting body condition or other colour traits. Conclusions/Significance Our results demonstrate that the expression of a sexually selected structural colour signal depends on the time at elevated body temperature affecting physiological performance but not on available energy gained from food per se in an ectothermic vertebrate. We suggest that the effect of high ambient temperature on UV colour in male L. viridis makes it an honest signal, because success in acquiring thermally favourable territories and/or effective behavioural thermoregulation can both be linked to individual quality.Peer reviewe

Electrical properties and non-volatile memory effect of the [Fe(HB(pz)3)2] spin crossover complex integrated in a microelectrode device

We report on the deposition of thin films of the [Fe(HB(pz)3)2] (pz = pyrazolyl) molecular spin crossover complex by thermal evaporation. By means of impedance measurements and Raman microspectroscopy, we show that the films maintain the structure and properties of the bulk material. The conductivity of the films decreases by ca. 2 orders of magnitude when the freshly deposited compound goes through a first (irreversible) thermal phase change above ca. 380 K. This property can be exploited as a non-volatile (read-only) memory effect

On the Safety of Connected Cruise Control: Analysis and Synthesis with Control Barrier Functions

Connected automated vehicles have shown great potential to improve the efficiency of transportation systems in terms of passenger comfort, fuel economy, stability of driving behavior and mitigation of traffic congestions. Yet, to deploy these vehicles and leverage their benefits, the underlying algorithms must ensure their safe operation. In this paper, we address the safety of connected cruise control strategies for longitudinal car following using control barrier function (CBF) theory. In particular, we consider various safety measures such as minimum distance, time headway and time to conflict, and provide a formal analysis of these measures through the lens of CBFs. Additionally, motivated by how stability charts facilitate stable controller design, we derive safety charts for existing connected cruise controllers to identify safe choices of controller parameters. Finally, we combine the analysis of safety measures and the corresponding stability charts to synthesize safety-critical connected cruise controllers using CBFs. We verify our theoretical results by numerical simulations.Comment: Accepted to the 62nd IEEE Conference on Decision and Control. 6 pages, 5 figure