• Title/Summary/Keyword: bus service

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Vulnerability Assessment of a Large Sized Power System Using Neural Network Considering Various Feature Extraction Methods

  • Haidar, Ahmed M. A;Mohamed, Azah;Hussian, Aini
    • Journal of Electrical Engineering and Technology
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    • v.3 no.2
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    • pp.167-176
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    • 2008
  • Vulnerability assessment of power systems is important so as to determine their ability to continue to provide service in case of any unforeseen catastrophic contingency such as power system component failures, communication system failures, human operator error, and natural calamity. An approach towards the development of on-line power system vulnerability assessment is by means of using an artificial neural network(ANN), which is being used successfully in many areas of power systems because of its ability to handle the fusion of multiple sources of data and information. An important consideration when applying ANN in power system vulnerability assessment is the proper selection and dimension reduction of training features. This paper aims to investigate the effect of using various feature extraction methods on the performance of ANN as well as to evaluate and compare the efficiency of the proposed feature extraction method named as neural network weight extraction. For assessing vulnerability of power systems, a vulnerability index based on power system loss is used and considered as the ANN output. To illustrate the effectiveness of ANN considering various feature extraction methods for vulnerability assessment on a large sized power system, it is verified on the IEEE 300-bus test system.

Allocation of Real Power losses to Individual Loads Under Competition of Deregulated Power Industries (전력산업의 경쟁체제에서 유효전력 손실을 부하에 배분하는 방법)

  • Ro, Kyoung-soo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.18 no.6
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    • pp.114-120
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    • 2004
  • The paper proposes a method calculate the allocations of real power losses in transmission lines to individual loads based on loss distribution factors and compares them with those using marginal loss factors. The proposed method is implemented by defining loss distribution factors and analysing the individual loads' shares in the transmission line losses. Computer simulations on a 9-bus sample system verify effectiveness of the algorithm proposed and give an assertion that it is desirable to allocate power losses to loads using loss distribution factors rather than based on marginal loss factors.

A Case Study on Hardware Trojan: Cache Coherence-Exploiting DoS Attack (하드웨어 Trojan 사례 연구: 캐시 일관성 규약을 악용한 DoS 공격)

  • Kong, Sunhee;Hong, Bo-Uye;Suh, Taeweon
    • Proceedings of the Korea Information Processing Society Conference
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    • 2015.10a
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    • pp.740-743
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    • 2015
  • The increasing complexity of integrated circuits and IP-based hardware designs have created the risk of hardware Trojans. This paper introduces a new type of threat, the coherence-exploiting hardware Trojan. This Trojan can be maliciously implanted in master components in a system, and continuously injects memory read transactions on to bus or main interconnect. The injected traffic forces the eviction of cache lines, taking advantage of cache coherence protocols. This type of Trojans insidiously slows down the system performance, incurring Denial-of-Service (DoS) attack. We used Xilinx Zynq-7000 device to implement and evaluate the coherence-exploiting Trojan. The malicious traffic was injected through the AXI ACP interface in Zynq-7000. Then, we collected the L2 cache eviction statistics with performance counters. The experiment results reveal the severe threats of the Trojan to the system performance.

Study on Access Mode System related to the Passenger of KTX Gwangmyung Station : Focused on Electric Shuttle Train (KTX 광명역 이용객의 연계교통에 관한 연구 - 셔틀전동열차를 중심으로 -)

  • Cho, Ki-Han;Bang, Chang-Hoon;Han, Eun-Young
    • Proceedings of the KSR Conference
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    • 2008.11b
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    • pp.1833-1838
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    • 2008
  • With the opening of a KTX on April 1st, 2004, Gwangmyung Station was opened. It is a station for KTX only. As it is not located at the center of a city, it doesn't have as good access mode system as Seoul, Deajun Station. In addition, because it is constructed within a limited development district, the development of catchment areas is not enough. At the beginning of the opening, demand falls short of their expectation so Importance of Access Mode System is issued. For the revitalization of Gwangmyung Station, Korea National Railroad focuses on the construction of Access Mode System such as the beginning of shuttle bus service between Kwan-ak and Gwangmyung station on June, 2005, opening of shuttle electric train between Yongsan and Gwangmyung station December, 2006, and the completion of parking tower in Gwangmyung station. After opening to Access Mode System, demand has been increasing. As market is changing, the railway line capacity between Seoul and Siheung reaches a limit, this research tries to review the way to setup sufficient Access Mode System.

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Digital Fabrication Integrated Architectural Design Process based on Lean startup (Lean startup 방법을 적용한 디지털 패브리케이션 통합 건축 설계 프로세스)

  • Jung, Jae-hwan;Kim, Sung-Ah
    • Journal of KIBIM
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    • v.8 no.4
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    • pp.23-33
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    • 2018
  • Recently, the industry actively adopts the cutting-edge technologies of the fourth industrial revolution and uses them to enhance the productivity and service of mass-customization. The manufacturing industry is creating new processes and business models by achieving digital transformations through a lean start-up approach aimed at achieving the highest customer satisfaction with minimal resources. Although attempts are made to manufacture the building by introducing the latest technology in architecture, it is applied sporadically, not as an integrated system, in the entire phase of the architectural project. This paper analyzes the changes in the construction industry through the application of core technologies of the fourth industrial revolution. Design processes are analyzed for the digital transformation of the construction industry by case study of advanced architectural design practice. A novel design concept model 'Architectural lean startup' is proposed by combining the architectural process and the lean start up method. Through the design of the bus stop based on the architectural lean startup concept, it is confirmed that the designer repeats the 'Generate-Test-Analysis' to develop the design and generate the final result.

Design of Public Transportation Route Guidance System for Wheelchair Users Utilizing Public Data of Seoul City

  • Geumbi, Lee;Humberto, Villalta;Seunghyun, Kim;Kisu, Kim;Jaehyeong, Go;Yongjoo, Jun;Kwang Sik, Kim
    • International Journal of Internet, Broadcasting and Communication
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    • v.15 no.1
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    • pp.97-112
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    • 2023
  • The purpose of this study is to design and test a new way of public transportation route guidance system for persons with disabilities, including wheelchair users. The guidance system is smartphone app-based, using, routes that involve disabled-friendly facilities in the vicinity can be searched. A database that contains publicly available data on low-floor bus services, location and extent of disabled-friendly facilities, and suitable subways and stations, was developed for this purpose. The app uses the database to access and query the required information. A pilot study was conducted to test the effectiveness of the guidance system. It was found that the system was able to convey information about the disabled-friendly routes and related guidance information even inside subway stations, effectively. The performance of the system was compared with route guidance services that do not explicitly use data on disabled-friendly services. A notable difference was observed in the travel time estimated by this program and other guidance services. The difference was around 4 to 15 minutes. This is significant savings for persons with disabilities if they use the app and service. The study thus shows that exclusive use of disabled-friendly data in route guidance will bring more benefits for persons with disabilities.

Bi-LSTM VAE based Intrusion Detection System for In-Vehicle CAN (Bi-LSTM VAE 기반 차량 CAN 침입 탐지 시스템)

  • Kim, Yong-Su;Kang, Hyo-Eun;Kim, Ho-Won
    • Proceedings of the Korea Information Processing Society Conference
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    • 2022.05a
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    • pp.531-534
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    • 2022
  • 승차 공유, 카풀, 렌터카의 이용률이 증가하면서 많은 사용자가 동일한 차량에 로컬 액세스 할 수 있는 시나리오가 더욱 보편화됨에 따라 차량 네트워크에 대한 공격 가능성이 커지고 있다. 차량용 CAN Bus Network에 대한 DoS(Denial of Service), Fuzzy Attack 및 Replay Attack과 같은 공격은 일부 ECU(Electronic Controller Unit) 비활성 및 작동 불능 상태를 유발한다. 에어백, 제동 시스템과 같은 필수 시스템이 작동 불가 상태가 되어 운전자에게 치명적인 결과를 초래할 수 있다. 차량 네트워크 침입 탐지를 위하여 많은 연구가 진행되고 있으나, 기존 화이트리스트를 이용한 탐지 방법은 새로운 유형의 공격이 발생하거나 희소성이 높은 공격일 때 탐지하기 어렵다. 본 논문에서는 인공신경망 기반의 CAN 버스 네트워크 침입 탐지 기법을 제안한다. 제안하는 침입 탐지 기법은 2단계로 나누어 진다. 1단계에서 정상 패킷 분포를 학습한 VAE 모형이 이상 탐지를 수행한다. 이상 패킷으로 판정될 경우, 2단계에서 인코더로부터 추출된 잠재변수와 VAE의 재구성 오차를 이용하여 공격 유형을 분류한다. 분류 결과의 신뢰점수(Confidence score)가 임계치보다 낮을 경우 학습하지 않은 공격으로 판단한다. 본 연구 결과물은 정보보호 연구·개발 데이터 첼린지 2019 대회의 차량 이상징후 탐지 트랙에서 제공하는 정상 및 3종의 차량 공격시도 패킷 데이터를 대상으로 성능을 평가하였다. 실험을 통해 자동차 제조사의 규칙이나 정책을 사전에 정의하지 않더라도 낮은 오탐율로 비정상 패킷을 탐지해 낼 수 있음을 확인할 수 있다.

Balanced DQDB Applying the System with Cyclic Service for a Fair MAC Procotol (공정한 MAC 프로토콜을 위해 순환서비스시스템을 적용한 평형 DQDB)

  • 류희삼;강준길
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.12
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    • pp.1919-1927
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    • 1993
  • A new MAC protocol has been proposed and analysed to relieve the unfairness problems exhibited by the basic version of the DQDB standard. DQDB MAC protocol has the unfairness problems in throughputs. message delay and so or. And when the slots are reused or the file transmissions takes long, the unfairness problems in the system become worse. The new access protocol proposed here, which of called the Balanced DQDB, guarantees a fair bandwidth distribution by using one bit of the dual bus network protocol and keeps up all characteristics of DQDB. the DQDB analysis model introduced by Wen Jing, et al, was considered to analyse a sequential balance distribution of solts. And the probabilities of the empty in operation mode were represented to determine the probabilities for busy bits to generate on each node of the bus using the Markov chain. Through the simulations. the performances of the proposed Balanced DQDB and that of the standard DQDB of the BWB mechanism were compared at the state that the values of the RQ or CD counter on each node varied dynamically. As the results, it is shown that the Balanced DQDB has the decrement of throughputs in upstream, but the numbers of the used empty slots at each node of the Balanced DQDB had more than that of the others because the Balanced DQDB has over 0.9 throughputs in the 70~80% nodes of total node and it has constant throughputs at each node. And there results were analogous to that of the analytical model.

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A Comparative Study on the Travel Behavior of Residents by Housing Types and Implication Deduction for TOD Implementation (TOD구현을 위한 주택유형별 거주자의 통행행태 비교 분석 및 시사점도출)

  • Lee, Kyu Jin;Park, Kwan Hwee;Choi, Keechoo
    • Journal of Korean Society of Transportation
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    • v.32 no.1
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    • pp.27-38
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    • 2014
  • Recently, urban and transportation planning for Transit Oriented Development(TOD) has become a major issue. For the effective policy implementation of TOD, it is important to understand the travel behavior of residents in housing areas. In this study, we compared the travel behaviors of residents by housing types based on 'the 2010 Household Travel Survey Data' focusing on metropolitan areas. By building an estimation model for subway trip frequency by housing types, it was identified that the factors influencing subway trips and ultimately suggested implications to increase the use of the subway. The highest share of bus mode was for detached house residents with 22.8%, whereas the share of subway mode was highest by efficiency apartment residents with 17.5%. Walking distance to the subway from efficiency apartment and row house were verified as 661meters and 749meters. As the residents of each housing type have more cars and bicycles, their subway trips were decreased. It was also found that subway trips were increased when the population density of residence was high with good accessibility to subway stations and poor accessibility to bus service. In this study, the statistical findings to differentiate the planning factors of public transportation by housing types were also provided. The results of this study would be used for urban design considering the travel behaviors of residents by housing types and can also be utilized for promoting the patronage of public transportation. Some limitations and a future research agenda have also been discussed.

An Analysis of Spatial Accessibility to Public Healthcare Services in Rural Areas (농촌지역 공공 보건서비스에 대한 공간적 접근성 분석)

  • Cho, Dae-Heon;Shin, Jung-Yeop;Kim, Kam-Young;Lee, Gun-Hak
    • Journal of the Korean association of regional geographers
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    • v.16 no.2
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    • pp.137-153
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    • 2010
  • The issue of spatial equity in public healthcare services is an important issue in rural areas with lower healthcare resources. This study investigates spatial accessibility to public healthcare services by public transport, focusing on bus travel in Yeoju-gun, Gyeonggi-do. We comprehensively analyzed the spatial patterns of accessibility using the measures based on spatial interaction, and compared them with the accessibility patterns by car travel. As a result of analysis, the spatial disparity between the central part of Yeoju-gun (lower accessibility) and its peripheries (higher accessibility) was identified. More specifically, the area and population of lower accessibility areas are greater than those of higher accessibility areas, and the difference in the accessibility values between higher and lower accessible areas is considerably large. Moreover, the accessibility patterns appears somewhat different according to two different travel modes. In particular, about 20% of the entire area presented the opposite patterns between two travel modes. Interestingly, less populated peripheral areas are more included in higher accessible areas by car.

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