• ETRI Journal
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• v.39 no.2
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• pp.213-221
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• 2017

The advent of wireless access in vehicular environments (WAVE) technology has improved the intelligence of transportation systems and enabled generic traffic problems to be solved automatically. Based on the IEEE 802.11p standard for vehicle-to-anything (V2X) communications, WAVE provides wireless links with latencies less than 100 ms to vehicles operating at speeds up to 200 km/h. To date, most research has been based on field test results. In contrast, this paper presents a numerical analysis of the V2X broadcast throughput limit using a path loss model. First, the maximum throughput and minimum delay limit were obtained from the MAC frame format of IEEE 802.11p. Second, the packet error probability was derived for additive white Gaussian noise and fading channel conditions. Finally, the maximum throughput limit of the system was derived from the packet error rate using a two-ray path loss model for a typical highway topology. The throughput was analyzed for each data rate, which allowed the performance at the different data rates to be compared. The analysis method can be easily applied to different topologies by substituting an appropriate target path loss model.

• BMB Reports
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• v.45 no.1
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• pp.47-50
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• 2012

The International HapMap Project and the Human Genome Diversity Project (HGDP) provide plentiful resources on human genome information to the public. However, this kind of information is limited because of the small sample size in both databases. A Genome-Wide Association Study has been conducted with 8,842 Korean subjects as a part of the Korea Association Resource (KARE) project. In an effort to build a publicly available browsing system for genome data resulted from large scale KARE GWAS, we developed the KARE browser. This browser provides users with a large amount of single nucleotide polymorphisms (SNPs) information comprising 1.5 million SNPs from population-based cohorts of 8,842 samples. KAREBrowser was based on the generic genome browser (GBrowse), a web-based application tool developed for users to navigate and visualize the genomic features and annotations in an interactive manner. All SNP information and related functions are available at the web site http://ksnp.cdc. go.kr/karebrowser/.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.6
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• pp.837-844
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• 2001

Jet cutting technology currently makes use of a generic supersonic gas jet to improve the cutting speed and performance. In order to get a better understanding of the flow characteristics involved in the supersonic jet cutting technology, the axisymmetric Navier-Stokes equations have been solved using a fully implicit finite volume method. Computations have been conducted to investigate some major characteristics of supersonic coaxial turbulent jets. An assistant gas jet has been imposed on the primary gas jet to simulate realistic jet cutting circumstance. The pressure and the temperature ratios of the primary and assistant gas jets are altered to investigate the major characteristics of the coaxial jets. The total pressure and Mach number distributions, shock wave systems, and the jet core length which characterize the coaxial jet flows are strongly affected by the pressure ratio, but not significantly dependent on the total temperature ratio. The assistant gas jet greatly affects the basic flow characteristics of the shock system and the core length of under and over-expanded jets.

• Proceedings of the CALSEC Conference
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• 2005.11a
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• pp.78-84
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• 2005

As the research activities related to 'Ubiquitous Computing' whose concept was introduced by Mark Weiser are growing, RFID(Radio Frequency Identification) technology has recently gained attention as a technology to advance the ubiquitous computing and a lot of related researches are also in progress. Research works done so far are mainly linked to the situation that the research outputs apply to meet the requirements for asset tracking and data sharing with partners over supply chain by using fixed RFID readers. However, it is essential that users have access to real-time information about the tagged objects and services whenever and wherever they want in the era of ubiquitous computing, so mobile devices-including PDA, smart phone, cellular phone, etc - which are equipped with an RFID reader can be regarded as an essential terminal for users living in ubiquitous computing environment. As far as the application with mobile devices are concerned, there are many considerations due to their limited capabilities of data processing, battery consumption and so on. In this paper, we review the generic RFID network model and introduce the revised RFID network model in consideration of incorporation with mobile devices equipped with an RFID reader. Also, we derive the requirements for software embedded within an RFID- enabled mobile terminal and then discuss essential components for implementation. Moreover, we develop the applications for asset management at museum by using mobile RFID network model.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.5
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• pp.683-692
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• 1995

Many kinds of large scale multiprocessing and parallel-processing systems have recently been developed. The contention on the shared data caused by multiple processors may degrade system performance. So, processor synchronization has become one of the important issues in these systems. To solve the synchornization issues, a lot of software and hardware schemes based on spin lock have been proposed. Although software schemes are easy to implement, hardware schemes are preferred in many systems to gain optimized performance. This paper proposes an efficient processor synchronization scheme, called QCX,and describes its design considerations, hardware, algorithm, protocol. Also, in this paper, the performance of QCX has been evaluated with QOLB[5] and LBP[7] using a simulation. The simulation, with varying the number of processor and the contention on shared variables, measured the average execution times of a workload. The simulation results show that the performances of QCX is best when practicability is considered. QCX is more efficient than QOLB and LBP in two aspects. First, the hardware of QCX is more simple and cost-effective because the cache structure need not be changed. Secondly, QCX is more general because it uses a generic atomic instruction.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.149-155
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• 2004

This paper presents how to find proper operating points of FACTS devices to enhance the steady-state security level considering line contigency analysis. Three generic types of FACTS devices such as series controllers, shunt controllers, and series-shunt controllers are introduced and applied to moximize a security margin and to minimize security indices. Security indices related to line flows and bus voltages are utilized and minimized iteratively in this paper. Contingency analysis is performed to detect the most severe single line fault. In various load conditions, FACTS devices are tested to establish appropriate preventive or corrective action without generation re-dispatching or load shedding. The FACTS operation scheme is verified on the IEEE 57-bus system in a line-faulted contingency.

• Journal of Mechanical Science and Technology
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• v.14 no.10
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• pp.1051-1060
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• 2000

Linear cyclic systems (LCS's) are a class of systems whose dynamic behavior changes cyclically. Such cyclic behavior is ubiquitous in systems with fundamentally repetitive motions (e. g. all rotating machinery). Yet, the knowledge of the noise and vibration transmission paths in LCS's is quite limited due to the time-varying nature of their dynamics. The first part of this two-part paper derives a generic expression that describes how the noise and/or vibration are transmitted between two (or multiple) locations in the LCS's. An analysis via the Fourier series and Fourier transform (FT) plays a major role in deriving this expression that turns out to be transfer function dependent upon the cycle position of the system. The cyclic nature of the LCS' transfer functions is shown to generate a series of amplitude modulated input signals whose carrier frequencies are harmonic multiples of the LCS' fundamental frequency. Applicability of signal processing techniques used in the linear time-invariant systems (LTIS's to the general LCSs is also discussed. Then, a criterion is proposed to determine how well a LCS can be approximated as a LTIS. In Part II, experimental validation of the analyses carried out in Part I is provided.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11b
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• pp.1297-1300
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• 2003

본 논문은 웹 온톨로지 데이터를 접근, 표현 및 처리 할 수 있는 온톨로지 객체 모델을 생성하기 위한 시스템이다. 시멘틱 웹의 대두로 인해 웹 상에 존재하는 데이터의 특성에 따라서 접근 할수 있는 방법도 다양화 되었다. 이에 웹 상에서 산재되어 있는 지식들을 가져와 각 도메인에 맞게 새로운 온톨로지를 생성하고 서로 다른 언어로 표현된 온톨로지를 계층 어휘들을 이용하여 시멘틱웹 환경에서 지식을 처리하기 위해 웹 온톨로지를 구축하고 처리할 수 있는 온톨로지 객체 모델을 제공하고, 온톨로지 객체 모델 API를 통해 외부 어플리케이션과의 정보를 교환한다. 본 논문에서는 웹 온톨로지를 표현하기 위한 모델을 계층별로 구별하여 프레임 기반의 상위 온톨로지(frame-based ontology layer), 다른 도메인에서도 사용이 가능한 공통된 어휘(vocabulary)를 표현한 핵심 온톨로지(generic ontology layer)와 각각의 온톨로지 언어에 의존적인 어휘를 표현한 기능 온톨로지(functional ontology layer)로 구성하여 표현의 중복을 없애고 재 사용성을 높이기 위한 모델을 제공함으로써, 온톨로지 추론, 병합 및 저작 도구 등의 외부 어플리케이션이 온톨로지 객체 모델에 손쉽게 접근할수 있고, 온톨로지에 대한 쉬운 지식 표현 및 핸들링을 제공할 수 있다.

• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.81-91
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• 2004

Although it is suggested that risk -based management plan is needed to manage air pollution effectively, we have no resources enough to evaluate all aspects of substances and set priorities. So we need to develop a logical and easy risk-based priority setting method. However, it if impossible that only one generic system that is consistent with all the use is developed. In this study, we proposed a human health risk based priority-setting method for hazardous air pollutants, and ranked priorities for this method. First of all, after investigating previous chemical ranking and scoring systems, we chose appropriate indicators and logics to goal of this study and made a chemical priority ranking method using these. As results, final scores in priority ranking method were derived for 25 substances, and ethylene oxide, acrylonitrile and vinyl chloride were included in high ranks. In addition, same substances were highly ranked when using default values like when using no default, but the scores of hydrofluoric acid and ryan and compounds were sensitive to default values. This study could be important that priorities were set including toxicity type and quality and local inherent exposure conditions and we can set area-specific management guidelines and survey plans as a screening tool.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.559-564
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• 2002

Cross-talk cancellation, inverse filter design or deconvolution in a generic term, is a vital process for a virtual sound realization in the stereo sound reproduction system. Most, if not all, of the design algorithms available for the inverse filter are based on a linearized model of the real physical plant. The result of such a plant-based design method, which may be referred to here as the indirect method, is biased due to both modelling and inversion errors. This paper presents a novel direct cross-talk cancellation method that may be free from the inversion error. The direct method can directly models the inverse filter by a suitable rearrangement of the input and output ports of the original plant so that no inversion is required here. Advantages are discussed with various experiments in an anechoic chamber using a PC soundcard. Binaural reproduction tests conducted showed that the conventional indirect method yields about 8 % reproduction performance error on both ear positions, whereas the direct method offers about 3 %.