• Journal of Information Display
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• v.11 no.2
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• pp.76-83
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• 2010

This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.15-20
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• 2005

This is a comparative study where we compare simulation results with model examining the time and direction the fire spreads when it breaks out. Also there is vertical distribution of temperature in carriage where the fire spreads out. This study is about demonstrating how to establish smokeless system in urban vehicle, about its necessity, and about vehicle system restructuring, This study also makes an effort to find more advanced method for efficient fire safety in trains, In existing vehicles, in case of fire, the smoke can't go out when doors are closed and hence it spreads in whole train. Even though the method of using ventilation or exhaust established inside the carriage to throw smoke out is much better than the way of opening end doors in each carriage, this study is trying to do research on second way. Through simulation we see that in second case, even though not as good as the first one, smoke can exit through gates. Even though the first method is better, the second can also be uses to let fire out. We can know that in the first case as the smoke can exit out faster, it provides more safety for people. So this system provides better fire safety condition.

• International Journal of Advanced Culture Technology
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• v.5 no.1
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• pp.58-63
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• 2017

Emergencies and disasters can happen any time without any warning, and things can change and escalate very quickly, and often it is swift and decisive actions that make all the difference. It is a responsibility of the building facility management to ensure that a proven evacuation plan in place to cover various worst scenario to handled automatically inside the facility. To mapping out optimal safe escape routes is a straightforward undertaking, but does not necessarily guarantee residents the highest level of protection. The emergency evacuation navigation approach is a state-of-the-art that designed to evacuate human livings during an emergencies based on real-time decisions using live sensory data with pre-defined optimum path finding algorithm. The poor decision on causalities and guidance may apparently end the evacuation process and cannot then be remedied. This paper propose a cloud connected emergency evacuation system model to react dynamically to changes in the environment in emergency for safest emergency evacuation using IoT based emergency exit sign system. In the previous researches shows that the performance of optimal routing algorithms for evacuation purposes are more sensitive to the initial distribution of evacuees, the occupancy levels, and the type and level of emergency situations. The heuristic-based evacuees routing algorithms have a problem with the choice of certain parameters which causes evacuation process in real-time. Therefore, this paper proposes an evacuee routing algorithm that optimizes evacuation by making using high computational power of cloud servers. The proposed algorithm is evaluated via a cloud-based simulator with different "simulated casualties" are then re-routed using a Dijkstra's algorithm to obtain new safe emergency evacuation paths against guiding evacuees with a predetermined routing algorithm for them to emergency exits. The performance of proposed approach can be iterated as long as corrective action is still possible and give safe evacuation paths and dynamically configure the emergency exit signs to react for real-time instantaneous safe evacuation guidance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.380-383
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• 2006

The media transport system is used in a printer, a ATM(Automated Tellor Machine), and so on. The media transport system has many problems through miniaturization and rapid transportation of these machines. In the paper feeding mechanism, it is important to feed the sheet without jamming under any conditions. To avoid sheet jamming, first we need to predict the behavior of the sheet exactly. In this paper, the analysis of media behavior is based on J. Stolte's studies. In all of OA machines, a flexible beam or plate is pushed from the channel. The motion may be constrained by guides. This leads to a transient and geometrically nonlinear problem. The behavior of paper is simulated by dynamic elastica theory. The shape of guide is represented by parametric cubic curve. But J. Stolte's studies did not considered contact condition between sheet and guide. So Klarbring's Model. will be applied. And the analysis of flexible media has to include aerodynamic effect for more exact behavior analysis, because the flexible media can be deformed drastically by a little force. Therefore aerodynamic force must be applied to the governing equation. Lastly, the simulation of this model is performed, and the experiment is performed for verification of this model. The experimental results of low exit velocity are consistent with the simulation results, however experimental results of high exit velocity do not agree well with analytical results. The reason is that there may be other effects like nip Phenomena

• Journal of IKEEE
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• v.23 no.2
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• pp.642-651
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• 2019

One of the most important research topics on intelligent transportation systems in recent years is detecting and recognizing a license plate. The license plate has a unique identification data on vehicle information. The existing vehicle traffic control system is based on a stop and uses a loop coil as a method of vehicle entrance/exit recognition. The method has the disadvantage of causing traffic jams and rising maintenance costs. We propose to exploit differential image of camera background instead of loop coil as an entrance/exit recognition method of vehicles. After entrance/exit recognition, we detect the candidate images of license plate using the morphological characteristics. The license plate can finally be detected using SVM(Support Vector Machine). Letter and numbers of the detected license plate are recognized using CNN(Convolutional Neural Network). The experimental results show that the proposed algorithm has a higher recognition rate than the existing license plate recognition algorithm.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.1-9
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• 2022

A design factor analysis was conducted to reduce the thrust reduction in the off-design, due to the driving of the aerospike pintle nozzle. The close (NPR 100) as well as the open (NPR 11) stroke were fixed, as under-expansion conditions. The pintle contour, pintle head radius (R), cowl angle (θ), and cowl exit length (L) were selected as design factors. The change in thrust was analyzed, using a verified numerical analysis technique. First, the pintle head radius and the length of the cowl exit had little influence on the thrust. The cowl angle changed the mass flow rate by affecting the effective nozzle throat area, and created a reverse pressure gradient at the cowl exit. As a result of applying the dual aerospike contour, it was confirmed that the thrust in the design-off increased by approximately 1.2%, compared to the reference case and by approximately 3.4% compared to the worst case.

• Journal of the Korea Society of Computer and Information
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• v.9 no.1
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• pp.71-77
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• 2004

In general, security server controls information of people who usually come to building. In order to exit and entrance, while they bring Identification card into contact with card reader, server admits them into building after asks whether their informations are or not in database. However if many People want to exit and entrance in all direction. it may give rise to a serious traffic congestion. Therefore the delay is due to server's overload. In this paper, we suggested IZA(Identification Zone Algorithm) in order to prevent of traffic congestion.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.469-473
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• 2009

The supersonic gas ejector, as gas dynamic appliance, has been applied for a long time because of simplicity and reliability. However, for the prediction of ejector performances with given parameters, that is, working gas pressure and the nozzle shape, it is necessary to raise accuracy of modelling for properties of ejector gas flow. The purpose of the represented work is to compare one-dimensional modelling and numerical results with experimental results. The ejector with a conic nozzle has been designed and tested (Mach number at the nozzle exit section was 3.31, the nozzle throat diameter - 6 mm). Working gas - nitrogen, was brought from system of gas bottles. Diameter of the mixture chamber at the nozzle exit section was limited by condensation temperature of nitrogen and equaled 20 mm. The one-dimensional theory predicted the minimal starting pressure equaled 8.18 bar (absolute) and 0.051 bar in the vacuum chamber. Accordingly the minimal starting pressure was 9.055 bar and 0.057 in the vacuum chamber bar have been fixed in experiment.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.455-460
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• 2007

본 논문에서는 지능형 주택의 필수 요소 기술의 하나인 사용자 신원을 파악하며 또한 현재 사용자의 위치를 추정하는데 직접적으로 사용이 가능한 방으로의 들어오고 나감 (즉, 출/입 행동)을 감지하는 효과적인 방법을 제안한다. 개발된 시스템은 [1]에 제안되었던 방법을 개선시킨 것으로 초음파 센서 및 PC를 이용하여 만들어졌던 시스템을 8bit 마이크로 컨트롤러를 사용한 임베디드 시스템의 형태로 구현하였다. 이와 더불어 복수개의 센싱 시스템에서 감지한 신호를 블루투스에 기반한 무선 전송 채널을 통해 1개의 중앙 컴퓨터로 전송하는 무선 센서 네트워크를 구성하였다. 이렇게 구성된 센서 네트워크를 통해 각 센싱 모듈이 검출한 사용자 인식 및 인식된 사용자의 출/입 이벤트를 기록, 저장하는 시스템을 구현하였다. 개발된 시스템은 임베디드 시스템의 특성에 적합하도록 기존 PC기반으로 개발된 알고리즘을 수정 개선하였고, 성능 검증을 위해 일반 가정집에 3개의 센싱 모듈을 설치하여 3명의 사용자를 대상으로 실험을 수행하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.3
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• pp.207-214
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• 2009

Crossover of nitrogen from cathode to anode is inevitable in typical membranes used in PEM fuel cells. This crossovered nitrogen normally accumulates in the hydrogen recirculation system at anode side channels. Excessive buildup of nitrogen in the anode side lowers the relative hydrogen concentration and finally affects the performance of fuel cell stack. So it is very important to analysis the nitrogen gas crossover at various operating conditions. In this study, characterization of nitrogen gas crossover in PEM fuel cell stack was investigated. The mass spectroscopy (MS) has been applied to measure the amount of the crossovered nitrogen gas at the anode exit. Results show that nitrogen gas crossover rate was affected by current density, anode and cathode stoichiometric ratio and operating pressure. Current density, anode stoichiometric ratio and anode operating pressure do not affect nitrogen crossover rate but anode exit concentration of nitrogen. Cathode pressure and stoichiometric ratio largely affect the nitrogen crossover rate.