The novel patch element shapes with the interdigital and multi-via structures for mushroom-type metasurface reflectors are proposed for controlling the reflection phases. The interdigital structure provides a wide reflection phase range by changing the depth of the interdigital fingers. In addition, the multi-via structure provides the higher positive reflection phases such as near +180°. The sufficient reflection phase range of 360° and the low polarization dependent properties could be confirmed by the electromagnetic field simulation. The metasurface reflector for the normal incident plane wave was designed. The desired reflection angles and sharp far field patterns of the reflected beams could be confirmed in the simulation results. The prototype reflectors for the experiments should be designed in the same way as the primary reflector design of the reflector antenna. Specifically, the reflector design method based on the ray tracing method using the incident wave phase was proposed for the prototype. The experimental radiation pattern for the reflector antenna composed of the transmitting antenna (TX) and the prototype metasurface reflector was similar to the simulated radiation pattern. The effectiveness of the proposed structures and their design methods could be confirmed by these simulation and experiment results.

This paper presents on-chip characterization of electrostatic discharge (ESD) impacts applied on the Si-substrate backside of a flip-chip mounted integrated circuit (FC-IC) chip. An FC-IC chip has an open backside and there is a threat of reliability problems and malfunctions caused by the backside ESD. We prepared a test FC-IC chip and measured Si-substrate voltage fluctuations on its frontside by an on-chip monitor (OCM) circuit. The voltage surges as large as 200mV were observed on the frontside when a 200-V ESD gun was irradiated through a 5kΩ contact resistor on the backside of a 350μm thick Si substrate. The distribution of voltage heights was experimentally measured at 20 on-chip locations among thinned Si substrates up to 40μm, and also explained in full-system level simulation of backside ESD impacts with the equivalent models of ESD-gun operation and FC-IC chip assembly.

Bus bunching often occurs in public transit system, resulting in a series of problems such as poor punctuality, long waiting time and low service quality. In this paper, we explore the influence of the discrete distribution of traffic operation state on the dynamic evolution of bus bunching. Firstly, we use self-organizing map (SOM) to find the threshold of bus bunching and analyze the factors that affect bus bunching based on GPS data of No. 600 bus line in Xi'an. Then, taking the bus headway as the research index, we construct the bus bunching mechanism model. Finally, a simulation platform is built by MATLAB to examine the trend of headway when various influencing factors show different distribution states along the bus line. In terms of influencing factors, inter vehicle speed, queuing time at intersection and loading time at station are shown to have a significant impact on headway between buses. In terms of the impact of the distribution of crowded road sections on headway, long-distance and concentrated crowded road sections will lead to large interval or bus bunching. When the traffic states along the bus line are randomly distributed among crowded, normal and free, the headway may fluctuate in a large range, which may result in bus bunching, or fluctuate in a small range and remain relatively stable. The headway change curve is determined by the distribution length of each traffic state along the bus line. The research results can help to formulate improvement measures according to traffic operation state for equilibrium bus headway and alleviating bus bunching.

This paper first introduces the structure of a shipboard equipment control cabinet and the preliminary design of electromagnetic shielding, then introduces the principle of low-frequency magnetic field shielding, and uses silicon steel sheet to shield the low-frequency magnetic field of shipboard equipment control equipment. Based on ANSYS Maxwell simulation software, the low-frequency magnetic field radiation emission of the equipment's conducted harmonic peak frequency point is simulated. Finally, according to MIL-STD-461G test standard, the low-frequency magnetic field radiation emission test is carried out, which meets the limit requirements of the standard. The low-frequency magnetic field shielding technology has practical value. The low-frequency magnetic field radiation emission simulation based on ANSYS Maxwell proposed in this paper is a useful attempt for the quantitative simulation of radiation emission.

In this paper, the author performed an electromagnetic field simulation of a typical bonding wire structure that connects a chip and a package, and evaluated the signal transmission characteristics (S-parameters). In addition, the inductance per unit length was extracted by comparing with the equivalent circuit of the distributed constant line. It turns out that the distributed constant line model is not sufficient because there are frequencies where chip-package resonance occurs. Below the resonance frequency, the conventional low-frequency approximation model was effective, and it was found that the inductance was about 1nH/mm.

We propose a penalty-based and constraint Bayesian optimization methods with an agent-based supply-chain (SC) simulator as a new Monte Carlo optimization approach for multi-echelon inventory management to improve key performance indicators such as inventory cost and sales opportunity loss. First, we formulate the multi-echelon inventory problem and introduce an agent-based SC simulator architecture for the optimization. Second, we define the optimization framework for the formulation. Finally, we discuss the evaluation of the effectiveness of the proposed methods by benchmarking it against the most commonly used genetic algorithm (GA) in simulation-based inventory optimization. Our results indicate that the constraint Bayesian optimization can minimize SC inventory cost with lower sales opportunity loss rates and converge to the optimal solution 22 times faster than GA in the best case.

In this paper, we construct the first efficient leakage-resilient CCA2 (LR-CCA2)-secure attribute-based encryption (ABE) schemes. We also construct the first efficient LR-CCA2-secure identity-based encryption (IBE) scheme with optimal leakage rate. To obtain our results, we develop a new quasi-adaptive non-interactive zero-knowledge (QA-NIZK) argument for the ciphertext consistency of the LR-CPA-secure schemes. Our ABE schemes are obtained by boosting the LR-CPA-security of some existing schemes to the LR-CCA2-security by using our QA-NIZK arguments. The schemes are almost as efficient as the underlying LR-CPA-secure schemes.

In order to expect the single event occurrence on highly integrated CMOS memory circuit, quantitative evaluation of charge sharing between memory cells is needed. In this study, charge sharing area induced by heavy ion incident is quantitatively calculated by using device-simulation-based method. The validity of this method is experimentally confirmed using the charged heavy ion accelerator.

In this work, an optimization method for the 3D container loading problem with multiple constraints is proposed. The method consists of a genetic algorithm to generate an arrangement of cargo and a fitness evaluation using a physics simulation. The fitness function considers not only the maximization of the container density and fitness value but also several different constraints such as weight, stack-ability, fragility, and orientation of cargo pieces. We employed a container shaking simulation for the fitness evaluation to include constraint effects during loading and transportation. We verified that the proposed method successfully provides the optimal cargo arrangement for small-scale problems with about 10 pieces of cargo.

The Smith method has been used to control physical plants with dead time components, where plant states after the dead time is elapsed are predicted and a control input is determined based on the predicted states. We extend the method to the symbolic control and design a symbolic Smith controller to deal with a nondeterministic embedded system. Due to the nondeterministic transitions, the proposed controller computes all reachable plant states after the dead time is elapsed and determines a control input that is suitable for all of them in terms of a given control specification. The essence of the Smith method is that the effects of the dead time are suppressed by the prediction, however, which is not always guaranteed for nondeterministic systems because there may exist no control input that is suitable for all predicted states. Thus, in this paper, we discuss the existence of a deadlock-free symbolic Smith controller. If it exists, it is guaranteed that the effects of the dead time can be suppressed and that the controller can always issue the control input for any reachable state of the plant. If it does not exist, it is proved that the deviation from the control specification is essentially inevitable.

In this paper, for the purpose of clarifying the desired ITS information and communication systems considering both safety and social feasibility to prevention overengineering, using a microscopic traffic flow simulator, we discuss the required information acquisition rate of three types of safety driving support systems, that is, the sensor type and the communication type, the sensor and communication fusion type. Performances are evaluated from the viewpoint of preventing overengineering performance using the “TsRm evaluation method” that considers a vehicle approaching within the range of R meters within T seconds as the vehicle with a high possibility of collision, and that evaluates only those vehicles. The results show that regarding the communication radius and the sensing range, overengineering performance may be estimated when all vehicles in the evaluation area are used for evaluations without considering each vehicle's location, velocity and acceleration as in conventional evaluations. In addition, it is clarified that the sensor and communication fusion type system is advantageous by effectively complementing the defects of the sensor type systems and the communication type systems.

Boarding is the last step of aircraft turnaround and its completion in the shortest possible time is desired. In this paper, we propose a new boarding strategy that outperforms conventional strategies such as the back-to-front strategy and the outside-in strategy. The Steffen method is known as one of the most efficient boarding strategies in literature, but it is hard to be realized in the real situation because the complete sorting of passengers in a prescribed order is required. The proposed strategy shows a performance close to that of the Steffen method and can be easily implemented by using a special gate system.

A neural network that outputs reconstructed images based on projection data containing scattered X-rays is presented, and the proposed scheme exhibits better accuracy than conventional computed tomography (CT), in which the scatter information is removed. In medical X-ray CT, it is a common practice to remove scattered X-rays using a collimator placed in front of the detector. In this study, the scattered X-rays were assumed to have useful information, and a method was devised to utilize this information effectively using a neural network. Therefore, we generated 70,000 projection data by Monte Carlo simulations using a cube comprising 216 (6 × 6 × 6) smaller cubes having random density parameters as the target object. For each projection simulation, the densities of the smaller cubes were reset to different values, and detectors were deployed around the target object to capture the scattered X-rays from all directions. Then, a neural network was trained using these projection data to output the densities of the smaller cubes. We confirmed through numerical evaluations that the neural-network approach that utilized scattered X-rays reconstructed images with higher accuracy than did the conventional method, in which the scattered X-rays were removed. The results of this study suggest that utilizing the scattered X-ray information can help significantly reduce patient dosing during imaging.

In this paper, we build a microscopic simulator of traffic flow in a three-modal transport society for pedestrians/slow vehicles/vehicles (P/SV/V) to evaluate a post P/V society. The simulator assumes that the SV includes bicycles and micro electric vehicles, whose speed is strictly and mechanically limited up to 30 km/h. In addition, this simulator adopts an SV overtaking model. Modal shifts caused by modal diversity requires new valuation indexes. The simulator has a significant feature of a traveler-based traffic demand simulation not a vehicle-based traffic demand simulation as well as new evaluation indexes. New assessment taking this situation into account is conducted and the results explain new aspects of traffic flow in a three-mode transport society.

Side-channel (SC) leakage from a cryptographic device chip is simulated as the dynamic current flowing out of the chip. When evaluating the simulated current, an evaluation by comparison with an actual measurement is essential; however, it is difficult to compare them directly. This is because a measured waveform is typically the output voltage of probe placed at the observation position outside the chip, and the actual dynamic current is modified by several transfer impedances. Therefore, in this paper, the probe voltage is converted into the dynamic current by using an EMC macro-model of a cryptographic device being evaluated. This paper shows that both the amplitude and the SC analysis (correlation power analysis and measurements to disclosure) results of the simulated dynamic current were evaluated appropriately by using the EMC macro-model. An evaluation confirms that the shape of the simulated current matches the measured one; moreover, the SC analysis results agreed with the measured ones well. On the basis of the results, it is confirmed that a register-transfer level (RTL) simulation of the dynamic current gives a reasonable estimation of SC traces.

Two structural coverage criteria, toggle coverage and modified condition/decision coverage, for FBD (Function Block Diagram) simulation are proposed in the previous study. This paper empirically evaluates how effective the coverage criteria are to detect faults in an FBD program using the mutation analysis.

According to the aging society, it is getting more important for software industry to secure human resources including senior developers. To enhance the performance of senior developers, we should clarify the strengths and weaknesses of senior developers, and based on that, we should reconsider software engineering education and development support tools. To a greater or lesser extent, many cognitive abilities would be affected by aging, and we focus on the human memory as one of such abilities. We performed preliminary analysis based on the assumption. In the preliminary experiment, we prepared programs in which the influence of human memory performance (i.e., the number of variables remembered in the short-term memory) on reading speed is different, and measured time for subjects to understand the programs. As a result, we observed that the code reading speed of senior subjects was slow, when they read programs in which the influence of human memory performance is larger.

This paper demonstrates how to achieve simulation-based strong attribute hiding against adaptive adversaries for predicate encryption (PE) schemes supporting expressive predicate families under standard computational assumptions in bilinear groups. Our main result is a simulation-based adaptively strongly partially-hiding PE (PHPE) scheme for predicates computing arithmetic branching programs (ABP) on public attributes, followed by an inner-product predicate on private attributes. This simultaneously generalizes attribute-based encryption (ABE) for boolean formulas and ABP's as well as strongly attribute-hiding PE schemes for inner products. The proposed scheme is proven secure for any a priori bounded number of ciphertexts and an unbounded (polynomial) number of decryption keys, which is the best possible in the simulation-based adaptive security framework. This directly implies that our construction also achieves indistinguishability-based strongly partially-hiding security against adversaries requesting an unbounded (polynomial) number of ciphertexts and decryption keys. The security of the proposed scheme is derived under (asymmetric version of) the well-studied decisional linear (DLIN) assumption. Our work resolves an open problem posed by Wee in TCC 2017, where his result was limited to the semi-adaptive setting. Moreover, our result advances the current state of the art in both the fields of simulation-based and indistinguishability-based strongly attribute-hiding PE schemes. Our main technical contribution lies in extending the strong attribute hiding methodology of Okamoto and Takashima [EUROCRYPT 2012, ASIACRYPT 2012] to the framework of simulation-based security and beyond inner products.

In this study, simulations are performed to design an optimal device for thinning the GaN channel layer on the semi-insulating layer in HEMT. When the gate length is 50nm, the thickness of the undoped channel must be thinner than 300nm to observe the off state. When the GaN channel layer is an Fe-doped, an on/off ratio of ~300 can be achieved even with a gate length of 25nm, although the transconductance is slightly reduced.

A method for estimating circuit performance variation caused by packaging-induced mechanical stress is proposed. The developed method is based on the stress distribution chart for the target integrated circuit (IC) and the stress sensitivity characteristics of individual devices. This information is experimentally obtained using a specially designed test chip and a cantilever bending calibration system. A post-packaging analysis and simulation tool, called Stress Netlist Generator (SNG), is developed for conducting the proposed method. Based on the stress distribution chart and the stress sensitivity characteristics, SNG modifies the SPICE model parameters in the target netlist according to the impact of the packaging-induced stress. The netlist generated by SNG is used to estimate packaging-induced performance variation with high accuracy. The developed method is remarkably effective even for small-scale ICs with chip sizes of roughly 1 mm2, such as power management ICs, which require higher precision.