The performance of a data center network is a key to provide high quality information services. As a topology for data center networks, a folded Clos network (FCN) is advantageous because it provides high throughput for arbitrary traffic patterns. To maximize the throughput of an FCN, traffic congestion must be avoided. This is achieved by uniformly diffusing flows between links. Thus, this paper investigates two distributed algorithms that nearly uniformly spread flows in FCNs. The first algorithm is executable with information that is locally obtainable at the source of a flow. This method is further divided into two versions. One version may reroute an existing flow for a flow completion, while the other does not perform rerouting. The second algorithm runs with semi-local information, which can be obtained via communication between the source and destination switches. These algorithms are executable in a distributed manner without relying on global information. This means that the processing overhead for these algorithms is small. This paper theoretically derives upper bounds on the number of flows that go through a link when these algorithms are applied. These bounds assure that the load offered on a link does not grow extremely heavy. This paper also evaluates the presented algorithms and conventional random routing for different traffic and network models through computer simulation. The results clearly show the advantage of the presented algorithms.
Slow traffic is a major environmental and economic problem, especially in crowded or developing cities. Often, slow traffic is blamed on “selfish” drivers that drive aggressively at the expense of others on the road. This research uses a multi-agent simulation to observe the effects of asocial behavior on a straight three-lane highway without bottlenecks or blockages. Results show that asocial behavior only benefits cars if they can move with instant reaction times, and has little to no benefit when even a 0.5s reaction time is introduced. Additionally, traffic jams were observed in the simulation, despite the lack of blockages on the road. These “phantom” jams persisted longer when cars had a longer reaction time.
Beginners of programming sometimes difficult situations and struggle for satisfactory achievement without special support from their environments. Moreover, such beginners, by themselves, often have to set up their programming environments and understand several types of errors from compilers and/or interpreters by themselves. Cloud services would support effective programming environments but they might not provide kind and adequate helps/assistance for beginners. It is necessary for us to employ suitable tools for effective learning of current computer language programming. We have designed and implemented a Web-based programming educational system with error analysis and visualization to support program learning of Python and Ruby for beginners. With this system, it will be more useful, helpful or fruitful for learners to write and execute programs very easily, to recognize many types of errors (noticing personal trends of occurred errors by themselves), and to utilize history of error-occurring and recovering in order to gain individual understanding and achievement of programming.
In this paper, we have investigated non-equilibrium effects for advanced MOSFETs by using a device simulator with quantum energy transport (QET) model. The QET model allows to simulate non-equilibrium carrier transport as well as quantum confinement. The QET model includes the mobility model as a function of carrier temperature in order to consider the non-local effects. We have simulated advanced MOSFETs down to 20 nm gate length using the QET model. The QET model is compared with the quantum drift diffusion (QDD) model which includes a mobility model with local assumptions. It is found that the non-local mobility model is needed to simulate the advanced MOSFETs with less than 40 nm.
In this paper, we have investigated the influence of optical phonon energy on electron saturation velocity and energy relaxation time by using a full band Monte Carlo simulator. The energy band structure is obtained using the first principle calculation. The scattering probability is calculated so as to conserve the energy and momentum in the full band structure. It is found that the range of optical phonon energy from 56.2 to 63.9 meV allows experimental saturation velocity and energy relaxation time. Electron saturation velocity is more sensitive than relaxation time to the optical phonon energy.
We investigated a fabrication technique of c-plane oriented hydroxyapatite (HA) crystalline film on low cost amorphous SiO2 substrates to apply the orientation-controlled HA crystal to disposal biochips. An experiment was conducted by the pulsed laser deposition (PLD) method. We showed that a high quality HA crystalline film was able to be grown by using a fluoroapatite (FA) buffer layer, which was self-oriented on amorphous SiO2. A relationship between a FA film thickness and the HA quality was examined with an aim of minimizing a toxic risk of F to biomolecules, even if it was eluted from FA. It was found that the thickness of the FA film could be reduced to about 7.5 nm, at the same time, the crystallinity and a smoothness of HA were also excellent. A crystal growth model of FA on the amorphous SiO2 was also studied. We considered that highly reactive F in a laser-ablated-plume substituted for O on the substrate surface, which became a migration trap, causing 3-dimensional island growth as FA crystal nuclei. This model consistently agreed with a series of experimental results.
The frequency analysis result of the electromagnetic wave due to the partial discharge has a large influence on the research result. If the characteristics of electromagnetic waves change depending on the distance from the partial discharge generating source, there is a possibility that obstruction of discharge characteristics may be hindered. In this research, electromagnetic waves were acquired while changing the distance between the partial discharge source and the antenna. As a result, it was found that the distance attenuation of the high frequency component included in the first pulse of the electromagnetic wave is small and the distance attenuation of the low frequency component is large. It is considered that the amplitude of the first pulse decreases with distance.
This paper proposes a new monitoring device for the detection of sleep apnea syndrome. Existing devices for detecting sleep apnea and hypopnea use a microphone attached to the neck to record respiratory sounds; however, such systems have limitations because they are based on the analysis of air flow, which may be insufficient for accurate monitoring and detection. In this study, we develop a device for measuring arterial blood oxygen saturation in the neck zone using photo plethysmography. The proposed method of estimating arterial blood oxygen saturation is validated by comparison with the device and pulse oximeter measurements in the neck zone.
The aim of this study was to clarify the dynamic relationship between the amount of milk flowing out from the tip of an artificial nipple and tongue movement. We constructed a model of an artificial nipple. We performed numerical value simulation using fluid analysis software and estimated the amount of milk-secreted. This study was conducted to reduce uneasiness that new mothers may feel about breast-feeding, helping to show the amount of milk-secreted per one time of breast-feeding.
Ship is rolled greatly due to the waves in bad weather. Rolling cause the ship to overturn or cause collapse of the load. The purpose of this study is to suppress the roll of ship. Rolling suppression of this study is controlled by steering. Rolling can be suppressed by steering, but turning also occurs and the ship disengages from the course. This study applies Generalized Minimum Variance Control (GMVC) to the steering system. GMVC is derived by minimizing the cost function, which include tracking error and operation amount. Further, GMVC is based on Auto-Regressive eXogeneous (ARX) model. This study designed a new algorithm of GMVC. ARX model is expressed as Single Input Multi Outputs (SIMO) system. Then the single input means ship's steering and the multi outputs mean ship's rolling angle and turning angular velocity. The SIMO model are identified by ship's experiments. The cost function of proposed GMVC has rolling suppression term, turning suppression term and operation amount term. The proposed GMVC is designed with servo type against the model error and the wave's rolling effect.
Virtual reference feedback tuning (VRFT) and fictitious reference iterative tuning (FRIT) are well-known as the data-driven tuning schemes for directly designing feedback controllers. These schemes have been already extended to two-degree-of-freedom (2DOF) control systems in recent years. The conventional design schemes of 2DOF controllers need a complicated two-stage tuning process. This paper describes a one-stage tuning scheme for the 2DOF control system using a fictitious exogenous signal based on a data-driven method. In the proposed scheme, 2DOF controllers are designed with one criterion, and the least squares method is applied to find the optimal set of 2DOF controller parameters. According to the proposed scheme, the reference models are determined based on the stability margin that is quantified by the sensitivity function. It is also possible to design a control system taking robustness into account. Finally, the effectiveness of the proposed scheme is numerically verified by using a simulation example.
In model based development (MBD) of the automobile industry, it is necessary to create a model including multiple physical characteristics. Integration testing of such models is not easy because of its cross-sectional development. In this paper, we propose an integration test method based on the law of energy conservation for multi-physics model. The proposed method is consisted of two steps. The first step is a model hierarchical representation considering the type of energy. The second step is an energy flow diagram based on the hierarchized model. In addition, by creating a model verification tool based on the proposed method, model verification becomes partially automatic. Through the numerical experiments, we show that the proposed method and verification tools have the possibility of judging whether the model is normal or not. In the numerical experiments, we use a model that is developed via MATLAB/Simlink®, MapleSim®, and IPG-CarMaker®.
This research proposes a controller design method for p-inputs/q-outputs multi-inputs multi-outputs (MIMO) systems which have a greater number of inputs variables than the number of output variables. Recently, data-driven controller design methods, that can directly derive control parameters from a set of closed-loop operating data under the conditions that cannot obtain physical models and/or accurate system parameters by system identification, has been received much attention. Although some data-driven controller design methods for MIMO systems with the same number of inputs/outputs have been proposed because there are many MIMO systems in industrial sites, there are few reports about the design methods for MIMO systems with p-inputs/q-outputs. In this research, a design method of a generalized minimum variance controller (GMVC) based on the principal component analysis (PCA) is proposed. In particular, obtained p number of inputs are reduced to q number of principal components by PCA. Moreover, a data-driven GMVC is designed for a system model construceted by the principal components and system outputs. The proposed method can derive good control parameters stably than a conventional method, and the method can reduce the number of adjustable parameters that must be set by an operator. The effectiveness of the proposed method is verified by simulation examples.
In recent years, a technique capable of accurately measuring the human body shape for manufacturing knitwear worn on the body is required. Measurement techniques mainly using optical systems are currently used, but measurement is limited by the color of the object. Also, since the measurement is limited only to the shape of the outermost surface of the object, it is necessary to remove the clothes at the time of measurement. In this research, in order to solve the above problem, we proposed a noncontact human body shape measurement method using ultrasonic wave and confirmed the effectiveness of the proposed method by shape measurement experiment on clothes state mannequin.
This paper presents passivity-based visual feedback control for an endpoint closed-loop system with a movable camera. In particular, we discuss a control scheme for the vehicle system that consists of two ground vehicles and a camera-mounted aerial vehicle. The objective of the system is that a controlled ground vehicle tracks a target ground vehicle by using only aerial vehicle's visual information. First, a brief summary of the estimation and pose error systems for the camera-mounted aerial vehicle is presented. Second, we design a novel nonlinear observer to estimate the pose of the controlled ground vehicle. Next, we propose a visual feedback control law for the constructed visual motion error system based on the passivity. After discussing stability analysis of the closed-loop system through Lyapunov stability theorem, we present L2-gain performance analysis that deals with the disturbance attenuation problem via dissipation systems theory. Finally, we provide simulation results and actual nonlinear experimental results using two ground vehicles and a camera-mounted aerial vehicle to illustrate the performance of the proposed control method.
In order to make a multi-joint wearable robot for assisting an user's motions on whole body trunk, this paper discusses the usefulness of control with contact force distribution between user and robot for ensuring the safety of the user. To ensure the safety with wearable assistive robots being different structure from the assisting part of the user, sensing and controlling contact force distribution applying to the user is desired. By utilizing the tactile pressure sensors on the robot's surface, the robot can measure physical contact force distribution as pressure distribution. In this paper, a control methodology based on general impedance control system with pressure distribution is presented. Then, the methodology is confirmed possibility to improve safety compared with conventional torque-base control methodology. In some basically simulations, the proposed control system can reduce power of maximum contact force applying to the user, indicating usability of contact force distribution information for improving safety of assist robots with different motions from assisting parts of the user.
An inspection support system for power distribution facility using Augmented Reality (AR) is proposed. Based on the analysis of the conventional workflow and corresponding issues, a visualization function for facility attributes and a checking function of facility condition are designed. A prototype system is compared with a conventional inspection support system by sixteen inspection-experiencers using questionnaire at a real site. The questionnaire consists of 17 statements on a five-point scale (1 (disagree) to 5 (agree)). The statements are categorized into six categories: usability, improvement of work quality, equalization of work quality, efficiency, applicability, and overall. The average score for each category is equivalent to or higher than that of the conventional system. Especially, the comparison result shows that the proposed AR system is effective for improving and equalizing of inspection quality.
In this paper, we discuss a system that can recognize and classify stress based on speech. The system was built using a deep neural network (DNN) embedding to improve the baseline system (i-vector), called x-vector. The i-vector system usually requires Linear Discriminant Analysis (LDA) for dimension reduction, followed by Probability Linear Discriminant Analysis (PLDA) for scoring. In this work, the Generalized Discriminant Analysis (GDA) based Gaussianized cosine kernel and Joint-PLDA was used to replace the LDA and PLDA, respectively. The SUSAS database was used for training, testing, and enrollment data of our proposed system. We assessed our proposed system's effectiveness compared to the baseline system using equal error rate (EER). The evaluation and experiment results show that our proposed system outperforms the baseline system.
We propose the optimization integrating an active learning of input-output relations with successively produced learning data. Here, a relaxed problem with several constraints selected from among an infinite number of inequality constraints to assure uniform accuracy to input-output relations is supposed firstly, and then inequality constraints corresponding to newly produced data are iteratively added to the relaxed problem. In this process, a global optimal solution with higher accuracy can be obtained under the assurance of approximation accuracy to input-output relations.
The charging facilities of electric vehicles (EV) include a base charging (BC) at a garage or parking lot, a destination charging (DsC) at a reached destination, and an in-route charging which is performed on the way. As the current domestic in-route charging mostly uses a quick charger (QC), these charging facilities can be categorized into three types: QC, DsC, and BC. In this study, we clarified the characteristics of these three charging facilities and the required portrait for social infrastructure by simulating the basic charging behavior of EV. As basic data on charging characteristics of EV users, the questionnaire results from EV users (864 people) conducted in March 2017 were used. First, we decided the charging rules of QC, DsC, and BC, and set the standard for charging and running model. The result shows that the shorter the distance between QCs, the smaller the amount of electricity charged by QC per EV. This result was in a good agreement with the spread of domestic QCs and the declining trend of charged electric energy per EV. Furthermore, We investigated several manner using three charging facilities, and the results show many effects by changing the battery capacity.
Typically, satellite tracking telescopes use GPS to obtain highly accurate time information. The second GPS week number rollover was occurred on April 7, 2019. Telescope tracking does not work properly when GPS data information fails. It is difficult to renovate the telescope system. In this paper, we describe that the problem was solved by the recalculation of the TLE elements.