An Efficient Simulation of Discrete Time Queueing Systems with Markov-modulated Arrival Processes

국광호,강성열,Kook Kwang-Ho,Kang Sungyeol 한국시뮬레이션학회 2004 한국시뮬레이션학회 논문지 Vol.13 No.3

The cell loss probability required in the ATM network is in the range of 10$^{-9}$ ∼10$^{-12}$ . If Monte Carlo simulation is used to analyze the performance of the ATM node, an enormous amount of computer time is required. To obtain large speed-up factors, importance sampling may be used. Since the Markov-modulated processes have been used to model various high-speed network traffic sources, we consider discrete time single server queueing systems with Markov-modulated arrival processes which can be used to model an ATM node. We apply importance sampling based on the Large Deviation Theory for the performance evaluation of, MMBP/D/1/K, ∑MMBP/D/1/K, and two stage tandem queueing networks with Markov-modulated arrival processes and deterministic service times. The simulation results show that the buffer overflow probabilities obtained by the importance sampling are very close to those obtained by the Monte Carlo simulation and the computer time can be reduced drastically.

TDX-10A 교환기의 AO/DI 서비스 수용 능력 평가

국광호,이강원,홍선미,김태일,임석구,Kook, Kwang-Ho,Lee, Kang-Won,Hong, Seon-Mi,Kim, Tae-Il,Lim, Seog-Ku 한국정보처리학회 2000 정보처리논문지 Vol.7 No.9

공중통신망을 통한 데이터 송수신율 효율적으로 제공하기 위하여 AO/DI란 서비스가 제안되고 있다. TDX-10A교환기에 의해 AO/DI서비스를 제공하고자 할 때 TDX-10A 교환기의 패킷처리용량이 AO/DI 서비스를 제공하기에 충분한 지를 분석하는 것이 필요하다. 시뮬레이션에 의해 분석한 결과 TDX-10A 교환기에 설계목표치인 50,000 ISDN 가입자가 수용될 때 AO/DI 서비스 가입자의 비율이 29% 정도가 될 때 까지는 현재의 교환기에 의해 서비스될 수 있으나 그 이상이 될 때에는 시스템의 패킷처리용량을 증가시킬 필요가 있음을 알 수 있다. An AO/DI service was proposed to efficiently provide data communication service through the public network. It is planned to provide AO/DI service by the TDX -lOA switching system. It is necessary to evaluate the packet handling capacity of the TDX -lOA switching system in order to know whether its capacity is sufficient enough to accomodate AO/DI service or not. Simulation results show that TDX -lOA switching system can meet GoS(Grade of Service) requirements for AP/DI service until the AOIOI subscription rate of the ~.OOO ISDN subscribers becomes 29%.

TDX-10A 교환기의 AO/DI 서비스 수용 능력 평가

국광호(Kwang Ho Kook),이강원(Kang Won Lee),홍선미(Seon Mi Hong),김태일(Tae Il Kim),임석구(Seog Ku Lim) 한국정보처리학회 2000 정보처리학회논문지 Vol.7 No.9

An AO/DI service was proposed to efficiently provide data communication service through the public network. It is planned to provide AO/DI service by the TDX-10A switching system. It is necessary to evaluate the packet handling capacity of the TDX-10A switching system in order to know whether its capacity is sufficient enough to accomodate AO/DI service or not. Simulation results show that TDX-10A switching system can meet GoS(Grade of Service) requirements for AO/DI service until the AO/DI subscription rate of the 50,000 ISDN subscribers becomes 29%.

철도 안전업무종사자에 대한 국내외 신체검사 제도의 비교 연구

국광호(Kook Kwang-Ho),신택현(Shin Tack-Hyun),한경록(Han Kyong-Rok),한상욱(Han Sang-Wook) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

Since the railroad accidents due to the human error occupy considerable proportion among the railroad accidents, it is necessary to study the propriety of the physical examination system for the railroad workers. Our government is promoting some systematic supplementation for railroad safety on the basis of the Railroad Safety Act. In this paper, we perform a comparative analysis of domestic and foreign physical examination systems for railroad workers. We also compare the physical examination system for public officials with that for railroad workers. Then we consult expert opinions of the Korean Society of Occupational and Environmental Medicine. Through the comparative analysis, we provide useful information that is needed to amend the physical examination system.

철도 기관사의 적성검사에 대한 연구

국광호(Kook Kwang-Ho),한상욱(Han Sang-Wook),한경록(Han Kyong-Rok) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

Since 1971, the aptitude test for domestic train drivers has been long maintained. With the revision of the Railroad Safety Act in 2006, the aptitude test was changed from the type of written and skill test into the type of question-and-answer and reaction test. However, the main structure of the test was not changed. In this paper, we focus our attention on the improvement of the present aptitude test. We surveyed on two groups, one is the railroad expert group and another is train driver"s group, questioning about the importance of the domestic and foreign aptitude test items. Based on the analysis, we suggest desirable aptitude test system for the railroad safety.

철도 안전업무종사자의 신체검사에 대한 연구

국광호(Kook Kwang-Ho),신택현(Shin Tack-Hyun),김준규(Kim Jun-Gyu) 한국철도학회 2007 한국철도학회 학술발표대회논문집 Vol.- No.-

Techniques related to railroad industry have progressed rapidly and the automation of work is prevailing. Since the railroad accidents due to the human error occupy considerable proportion among the railroad accidents, it is necessary to study the propriety of the physical examination system for the railroad workers. In this paper, we perform a comparative analysis of domestic and foreign physical examination systems for railroad workers. Through the comparative analysis, we suggest that test of the sleep-disorder be included in the physical examination.

IEEE 802.16 망을 위한 랜덤 액세스 기법

김명환,국광호,이강원,김영일,Kim, Myeong-Hwan,Kook, Kwang-Ho,Lee, Kang-Won,Kim, Young-Il 한국시뮬레이션학회 2008 한국시뮬레이션학회 논문지 Vol.17 No.4

IEEE 802.16 광대역 무선 액세스 망의 성능을 향상시키기 위해서는 하향 링크와 상향 링크의 효율을 향상시키는 것이 필요한데, 상향 링크의 효율을 향상시키기 위해서는 효율적으로 대역폭을 요청할 수 있는 random access 기법의 연구가 필요하다. 본 논문은 프레임 당 전송되고자 하는 메시지 수에 기초한 random access 기법인 RA_NBRM 기법과 conflict resolution 기법에 기초한 random access 기법인 RA_CRA 기법을 제안하고 시뮬레이션을 통하여 이들의 성능이 현재 IEEE 802.16 시스템에서 적용하고 있는 binary exponential backoff 기법보다 우수함을 보였다. To enhance the performance of the IEEE 802.16 broadband wireless access system, it is necessary to improve the efficiency of the radio link. The efficiency of the uplink can be improved by using more efficient random access method. As new random access methods, we propose a RA_NBRM method which is based on the number of bandwidth request messages and a RA_CRA method which is based on the conflict resolution algorithm. The simulation results show that the performance of the new methods is superior to that of the existing binary exponential backoff method.

개인정보의 안전성 확보조치 기준에서의 우선순위 정립에 관한 연구

김영희,국광호,Kim, Young Hee,Kook, Kwang Ho 한국융합보안학회 2014 융합보안 논문지 Vol.14 No.4

정보화 및 인터넷의 급속한 발전에 따라 개인정보를 취급하는 기업에서 개인정보의 안전한 취급 관리를 위한 조치를 취하지 않아 개인정보가 유출되고 오 남용되는 사례가 빈번히 발생하고 있다. 이에 국내에서는 개인정보주체의 프라이버시 보호와 피해를 줄이기 위해 개인정보보호 관련 법제를 강화하고 관련 법제를 바탕으로 개인정보처리자가 개인정보를 보호하기 위한 안전성 확보조치 기준을 마련하고 따르도록 하고 있다. 그러나 개인정보의 안전성 확보조치 기준항목의 경우 각 개인정보 처리 기업의 특성 및 항목별 중요도에 따른 우선 적용 기준 등이 고려되지 않아 이행에 어려움이 따르고 있다. 따라서 본 연구에서는 개인정보의 안전성 확보조치 기준들의 세부적인 사항들을 기존 문헌 연구와 관련 법률을 통해 평가 기준을 도출하고, 평가 기준의 정량화 및 계층화를 위해 KJ (Kawakita Jiro) 기법을 이용하여 유사기준 항목의 통합 및 그룹화를 하여 계층구조를 생성한다. 이렇게 생성된 계층 구조를 AHP (Analytical Hierarchy Process) 기법을 이용해 전문가 대상으로 가중치 산정하여 기업에서 보다 합리적이고 효율적인 개인정보보호를 위한 우선순위 제안을 목적으로 한다. With the rapid development of the Internet and information technology, a company that deals with personal information does not have proper action to protect personal privacy and not take measures for the safe handling and management of personal information. It generates the case to abuse of personal information occurring frequently. In order to focus the effort to reduce damage and protect the privacy of personal information entity and enhance privacy laws based on the connection method and the processing of personal information, Korea encourages a company to follow regulation by providing certain criteria. However, in the case of items of measures standard of safety of personal information such as priority applicable criteria in accordance with the importance of itemized characteristics and the company of each individual information processing is not taken into account, and there are some difficulties to execute. Therefore, we derive criteria by law and reviewing existing literature related, the details of the measures standard of safety of personal information in this study and generate a hierarchical structure by using the KJ method for layering and quantification of the evaluation in integration of the reference item similar and the grouping. Accordingly, the weights calculated experts subject using the AHP method hierarchical structures generated in this manner, it is an object of the proposed priority for privacy and efficient more rational enterprise.

DEA모형을 이용한 도시철도 운영기관의 효율성 분석(안전)

노선화(Sun-Hwa Roh),국광호(Kwang-Ho Kook),이현주(Hyun-Ju Lee) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.10

DEA기법을 이용한 철도수송의 효율성 측정

김현웅(Kim Hyun-Woong),국광호(Kook Kwang-Ho) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월

The objective of this paper is to measure the relative technical efficiency of Korean railway transport service. Previous studies on the efficiency in Korean railway service have carried out before the structural reform of Korean railway industry in 2004, whereas this study used the latest data which reflected the impact of reform. We analyzed the efficiency in Korean railway transport by means of measuring the technical efficiencies of other countries, these were estimated with data envelopment analysis. DEA has gained great popularity in measuring efficiency in transport industry, school, government, hospital and so on in recent years. This analysis could serve as peer to help improve performance of the railway management and operation.