204 research outputs found
Renegotiations and the Diffusion of a Technology with Positive Externalities
We consider the problem of technology transfer.We specifically treat a technology such that an adoption of the technology by a player increases the other players\u27 payoffs but may decrease the adopter\u27s own payoff. The technology is transferred through negotiations. The property of the technology gives players the incentive to deviate from the negotiation for free-riding on the other players\u27 adoptions.We formulate this situation by the theory of social situations and investigate whether full diffusion is possible provided that full diffusion achieves the social optimum. We show that full diffusion is always achieved in the initial negotiation when renegotiations are allowed after implementing an agreement, whereas full diffusion may fail to be achieved if no such renegotiation is allowed
Stable Sets of a Strategic Public Good Provision Game
We consider stable sets of a simple and symmetric strategicpublic good provision game.In particular, we consider stable sets where each one consists of strategy profiles that provide an identical level of the public good. We completely identify the public good provision levels to be supported by the stable sets for each number of players. This identification induces the following two observations. First, the efficient public good provision level is always supported by a stable set. Second, the public good provision levels at the stable sets are no lower than that at the (unique coalition-proof) Nash equilibrium. In fact, the stable sets support strictly higher public good provision levels than that at the Nash equilibrium if there are more than two players. Further, we give a welfare comparison between the stable sets and the Nash equilibrium by employing the coefficient of resource utilization
The Stable Set of the Social Conflict Game with Delegations: Existence, Uniqueness, and Efficiency
We investigate the stable sets of social conflict games by employing the framework of the (abstract) system by Greenberg (Theory of Social Situations: An Alternative Game theoretic Approach, Cambridge University Press, 1990).The social conflict game includes the prisoners\u27 dilemma and the chicken game.We show that the stable set may fails to exist in the system directly derived from the social conflict game.The stable set exists if and only if the strong equilibrium exists in the underlying game.We consider another system where an agent is prepared and each player is allowed to delegate his decision to the agent. Then, the stable set always exists and consists of Pareto efficient outcomes with a certain property. We also discuss the relationship between the strong equilibrium and the stable set for the model with delegations
Single-payoff farsighted stable sets in strategic games with dominant punishment strategies
We investigate the farsighted stable set in a class of strategic games with dominant punishment strategies. In this class of games, each player has a strategy that uniformly minimizes the other players’ payoffs for any given strategies of other players. We particularly investigate a special class of the farsighted stable sets each of which consists of strategy profiles yielding a single payoff vector. We call such farsighted stable sets as the single-payoff farsighted stable sets. We propose a concept called the inclusive set that completely characterizes the single-payoff farsighted stable sets in the strategic games with dominant punishment strategies. We also show that the set of payoff vectors yielded by the single-payoff farsighted stable sets is closely related to the strict -core in strategic games. Further, we apply the results to the strategic games where each player has two strategies and strategic games associated with some market models.First version: September 30, 2016Revised version: October 24, 201
Thermomechanical noise of arrayed capacitive accelerometers with 300-NM-gap sensing electrodes
2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), 18-22 June 2017.Thermomechanical noise of arrayed capacitive accelerometers with sub-micrometer sensing electrodes was evaluated. The unit accelerometer of the array was 80-μm square, designed as a proportional scale-down of a conventional single-axis accelerometer. Since the size effect shows the capacitance sensitivity per unit volume increases by proportional downsizing, a 10-by-10 array of the one-tenth sized unit accelerometer would have the same sensitivity of a single accelerometer of same occupied area. However, the thermomechanical noise needs to be controlled and reduced by vacuum encapsulation because size reduction causes noise increase. By measuring the electrical impedance at the resonant frequency, the damping coefficient was estimated using electrical equivalent circuit modeling. The estimated thermomechanical noise was reduced below 3 μg√VHZ by encapsulating at 100 Pa, which is low enough for instrumentation applications
Zernike generation with MEMS deformadle mirror actuated by electrostatic piston array
2018 IEEE Micro Electro Mechanical Systems (MEMS), 21-25 Jan. 2018.We report a low-voltage and large-displacement electrostatic deformable mirror for in vivo retinal imaging by adaptive-optics optical coherence tomography. The mirror utilizes an electrostatic piston actuator which allows bottom electrodes to move vertically to keep the gap small to maintain large actuation force at low actuation voltage. An 8-mm-diameter mirror device was fabricated from two components; the mirror part and the actuator part. The parts were assembled with 7-μm-gap defined by an SU-8 layer. We successfully demonstrated operation of the mirror in various Zernike modes
Electrostatic Micro Mirror Array with Batch-Fabricated Torsion Beam of Silicon Nanowire
2020 IEEE 33rd International Conference on Micro Electro Mechanical Systems (MEMS), 18-22 Jan. 2020.A new design of arrayed micro mirror device for a high performance spatial light modulator of high resonant frequency, large deflection angle with high mechanical reliability has been proposed. The mirror has 100-μm square plate of 5 μm thick, which is suspended by thin silicon nanowire of about 1 μm thick and wide. The device was fabricated using Bosch process and isotropic plasma etching. We successfully demonstrated array operation of 4×4 devices at relatively low actuation voltage (~20 Vpp) and large mechanical deflection amplitude (~9°). However, the deviation of vibration amplitude was large among unit resonators. By fitting the frequency response to the Duffing equation we found that self-enhancing actuation force caused by nonlinearity of the vertical combs was a main reason
Nanometer Order Separation Control of Large Working Area Nanogap Created by Cleavage of Single-Crystal Silicon Along {111} Planes Using a MEMS Device
Nanogaps with a large working area and a precisely controlled separation of about 1 to 20 nm has important applications in nano photonics, thermal management, power generation, chemical sensing, etc. However, an effective method of fabricating such nanogaps has not yet been established. In addition, it has been necessary to evaluate the dependence of physical characteristics of nanogaps on the separation, but it has been technically and economically difficult to develop such a system. In this study, we developed a MEMS device, which can produce nanogaps with a large area and parallel smooth surfaces by the (111) plane cleavage of a single crystal silicon beam and can change and measure the separation of nanogaps. Using this device, nanogap fabrication by cleavage and separation control were uninterruptedly carried out while maintaining the cleanliness of the gap surfaces in vacuum; a nanogap with a large smooth surface area of 30 μ m² was successfully controlled in the range of 14 nm–1.5 μ m. For a small separation of less than 100 nm, the control resolution was sufficiently high at 1 nm. This method is fully compatible with conventional fabrication technologies for not only MEMS but also other semiconductor devices and should contribute to the fabrication of devices that exhibit useful quantum effects with only minor modifications. 2022-007
The Functional Domain of GCS1-Based Gamete Fusion Resides in the Amino Terminus in Plant and Parasite Species
Fertilization is one of the most important processes in all organisms utilizing sexual reproduction. In a previous study, we succeeded in identifying a novel male gametic transmembrane protein GCS1 (GENERATIVE CELL SPECIFIC 1), also called HAP2 (HAPLESS 2) in the male-sterile Arabidopsis thaliana mutants, as a factor critical to gamete fusion in flowering plants. Interestingly, GCS1 is highly conserved among various eukaryotes covering plants, protists and invertebrates. Of these organisms, Chlamydomonas (green alga) and Plasmodium (malaria parasite) GCS1s similarly show male gametic expression and gamete fusion function. Since it is generally believed that protein factors controlling gamete fusion have rapidly evolved and different organisms utilize species-specific gamete fusion factors, GCS1 may be an ancient fertilization factor derived from the common ancestor of those organisms above. And therefore, its molecular structure and function are important to understanding the common molecular mechanics of eukaryotic fertilization. In this study, we tried to detect the central functional domain(s) of GCS1, using complementation assay of ArabidopsisGCS1 mutant lines expressing modified GCS1. As a result, the positively-charged C-terminal sequence of this protein is dispensable for gamete fusion, while the highly conserved N-terminal domain is critical to GCS1 function. In addition, in vitro fertilization assay of Plasmodium berghei (mouse malaria parasite) knock-in lines expressing partly truncated GCS1 showed similar results. Those findings above indicate that the extracellular N-terminus alone is sufficient for GCS1-based gamete fusion
Neighborhood food environment and body mass index among Japanese older adults: results from the Aichi Gerontological Evaluation Study (AGES)
<p>Abstract</p> <p>Background</p> <p>The majority of studies of the local food environment in relation to obesity risk have been conducted in the US, UK, and Australia. The evidence remains limited to western societies. The aim of this paper is to examine the association of local food environment to body mass index (BMI) in a study of older Japanese individuals.</p> <p>Methods</p> <p>The analysis was based on 12,595 respondents from cross-sectional data of the Aichi Gerontological Evaluation Study (AGES), conducted in 2006 and 2007. Using Geographic Information Systems (GIS), we mapped respondents' access to supermarkets, convenience stores, and fast food outlets, based on a street network (both the distance to the nearest stores and the number of stores within 500 m of the respondents' home). Multiple linear regression and logistic regression analyses were performed to examine the association between food environment and BMI.</p> <p>Results</p> <p>In contrast to previous reports, we found that better access to supermarkets was related to higher BMI. Better access to fast food outlets or convenience stores was also associated with higher BMI, but only among those living alone. The logistic regression analysis, using categorized BMI, showed that the access to supermarkets was only related to being overweight or obese, but not related to being underweight.</p> <p>Conclusions</p> <p>Our findings provide mixed support for the types of food environment measures previously used in western settings. Importantly, our results suggest the need to develop culture-specific approaches to characterizing neighborhood contexts when hypotheses are extrapolated across national borders.</p
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