• 한국경영과학회지
• /
• 제30권2호
• /
• pp.131-142
• /
• 2005

This paper proposes queueing models for a Web server system which is composed of an infinite-buffer main server and finite-buffer auxiliary server(s). The system is modeled by the level-dependent quasi-birth- death (QBD) process. Utilizing the special structure of the QBD, we convert the infinite level-dependent QBD into a finite level-independent QBD and compute the state probabilities. We then explore the operational characteristics of the proposed web-server models and draw some useful conclusions.

• 한국항행학회논문지
• /
• 제12권1호
• /
• pp.61-67
• /
• 2008

특정 목적을 달성하기 위해서 멀티미디어 시스템을 구축하고 운영하는 조직은, 보안수준을 결정하고, 보안대책을 구현하며, 보안대책의 효과를 유지하기 위해 관리를 하여야 한다. 멀티미디어 시스템이 보안수준을 결정하고 관리하기 위해서, 첫째, 조직은 보안 수준을 결정할 수 있어야 하고, 둘째, 보안 수준에 따라 보안대책을 수립하는 절차를 확립하여야 하며, 셋째, 보안대책이 적용되어야 하는 영역을 결정할 수 있어야 하고, 마지막으로 조직은 보안대책의 효과를 평가하고 개선할 수 있어야 한다. 본 논문에서는 멀티미디어 시스템에 대한 위협의 분석, 멀티미디어 자산의 중요도 분석에 기반하여 멀티미디어 시스템의 보안수준을 결정하는 방법을 제안하였다.

• International Journal of Advanced Culture Technology
• /
• 제6권3호
• /
• pp.187-192
• /
• 2018

Permeate alteration technique is compounded the steeple sway-tuner status of the gleam-differential realization level (GDRL) on the permeate realization morph. The realization level condition by the permeate realization morph system is associated with the sway-tuner system. As to search a dot of the dot situation, we are gained of the permeate value with character-dot by the output signal. The concept of realization level is composed the reference of gleam-differential level for alteration signal by the permeate tuner morph. Moreover displaying a steeple alteration of the GDRL of the average in terms of the sway-tuner morph, and permeate dot tuner that was the a permeate value of the far alteration of the $Per-rm-FA-{\alpha}_{AVG}$ with $14.63{\pm}1.23units$, that was the a permeate value of the convenient alteration of the $Per-rm-CO-{\alpha}_{AVG}$ with $8.28{\pm}0.97units$, that was the a permeate value of the flank alteration of the $Per-rm-FL-{\alpha}_{AVG}$ with $3.28{\pm}0.58units$, that was the a permeate value of the vicinage alteration of the $Per-rm-VI-{\alpha}_{AVG}$ with $0.51{\pm}0.10units$. The sway tuner will be to evaluate at the steeple ability of the sway-tuner morph with character-dot by the permeate realization level on the GDRL that is displayed the gleam-differential morph by the realization level system. Sway realization system will be possible to control of a morph by the special signal and to use a permeate data of sway tuner level.

• International Journal of Internet, Broadcasting and Communication
• /
• 제10권2호
• /
• pp.39-44
• /
• 2018

Wideness variation technique is compounded the smooth diffusivity-vibration status of the fulgurate-space realization level (FSRL) on the wideness realization morph. The realization level condition by the wideness realization morph system is associated with the diffusivity-vibration system. As to search a position of the dot situation, we are acquired of the wideness value with constructed-point point by the diffusivity upper structure. The concept of realization level is composed the reference of fulgurate-space level for variation signal by the wideness vibration morph. Further displaying a smooth variation of the FSRL of the maximum-minimum in terms of the diffusivity-vibration morph, and wideness position vibration that was the a wideness value of the far variation of the $Wid-rm-FA-{\alpha}_{MAX-MIN}$ with $23.24{\pm}3.37units$, that was the a wideness value of the convenient variation of the $Wid-rm-CO-{\alpha}_{MAX-MIN}$ with $7.83{\pm}1.32units$, that was the a wideness value of the flank variation of the $Wid-rm-FL-{\alpha}_{MAX-MIN}$ with $2.99{\pm}0.51units$, that was the a wideness value of the vicinage variation of the $Wid-rm-VI-{\alpha}_{MAX-MIN}$ with $0.51{\pm}(-0.01)units$. The diffusivity vibration will be to evaluate at the smooth ability of the diffusivity-vibration morph with constructed-point by the wideness realization level on the FSRL that is displayed the fulgurate-space morph by the realization level system. Diffusivity realization system will be possible to control of a morph by the special signal and to use a wideness data of diffusivity vibration level.

• 한국통신학회논문지
• /
• 제31권6A호
• /
• pp.563-574
• /
• 2006

본 논문에서는 OFDM(Orthogonal Frequency Division Multiplexing) 기반 다중 안테나 시스템의 링크레벨 성능 분석을 위하여 실제 전파 환경과 유사한 특성을 갖는 Ray-tracing 방식 채널의 하나인 SCM(Spatial Channel Model) 채널을 구현한다. 3GPP & 3GPP2 Spatial Channel AHG(Ad-hoc Group)에서 시스템레벨 성능 비교용으로 제안한 SCM 채널을 링크레벨 성능의 비교 분석을 위하여, 본 논문에서는 시스템레벨 채널에 대한 채널 계수 및 파라메터들을 링크레벨 성능 비교용으로 변환하여 구현한다. 모의실험을 통하여 구현한 SCM 채널의 특성을 검증하고, 이를 이용하여 기존의 OFDM 기반 MIMO (Multiple Input Multiple Output) 적용 시스템 및 스마트 안테나 적용 시스템에서의 실제적인 링크레벨 성능을 분석하고, 정확한 비교 검증을 위하여 SCM 채널과 동일한 파라메터를 적용한 I-METRA 채널 및 독립 채널 상황에서의 링크 레벨 성능을 함께 비교 분석한다. MIMO 및 스마트 안테나 적용 시스템에 대하여 여러 채널 환경에서 채널 상관도에 따른 링크레벨 성능을 분석함으로써, 채널 상관도의 영향에 따라 주어진 환경에 적합한 다중 안테나 시스템을 제안한다.

• 수산경영론집
• /
• 제33권2호
• /
• pp.31-48
• /
• 2002

This paper is aimed to analyze how to evaluate the choice of optimal management measures and level of control in fisheries management under the costly and imperfect management system by comparing with costless and perfect management system that is commonly assumed in the analysis of fisheries regulations. Fishermen would set the level of fishing efforts at the point where the marginal fishing profit for fishing effort is equal to the marginal level of fine under costly and imperfect management system. Therefore, under the case where the marginal fishing profit is higher than the marginal level of fine, the level of fishing efforts would be made at the point which is higher than the level of fishing efforts made under costless and perfect management system and is not a point where the economic profit is maximized in regulated fisheries. From this conclusion, the fishermens avoidance activities against regulations as well as the level of control in fisheries management substantially have an influence on the choice of fisheries management instruments. According to the analysis of optimal fisheries management policy, the economic profits in regulated fisheries are determined by the level of fisheries enforcement costs and total fishing profits, in which as enforcement costs increase the economic profits decrease. In addition, the economic profits vary in response to the level of control in avoidance activities. That is, as avoidance costs decrease, the economic profits increase. The determination of optimal level of control in fisheries management should be made at the point where the marginal regulation costs are equal to the marginal profits from regulated fisheries, in which marginal regulation costs are different according to the type of management measures. And the level of profits changes in response to different levels of avoidance activities. The management measure that can maximize the difference between the marginal regulation costs and marginal profits from regulated fisheries should be chosen as an optimal fisheries management instrument.

• 한국건설관리학회:학술대회논문집
• /
• 한국건설관리학회 2008년도 정기학술발표대회 논문집
• /
• pp.285-290
• /
• 2008

국토해양부에서는 건설산업의 정보화 수준을 향상시키고 건설 생산체계를 효율화시키기 위해서 건설 CALS(Continuous Acquisition & Life-cycle Support)사업을 추진하고 있다. 건설CALS사업은 1998년부터 시작되었지만 건설CALS의 정보화수준은 어느 정도인지에 대한 측정이 없었다. 본 연구에서는 선행연구에서 도출된 평가지표를 사용하여 건설CALS의 정보화수준을 측정하였다. 연구는 설문항 및 표본 구성, 설문조사, 설문조사 결과 분석의 절차로 진행하였다. 설문조사 결과, 빠른 시스템 장애복구, 시스템의 웹환경 구축, 높은 표준분류체계 활용, 체계적인 정보전략 계획 수립 측면에서 우수한 것으로 판단된다. 본 연구에서 제시하는 결과는 건설CALS의 정보화수준을 정확히 파악하는데 기여할 것이라 생각된다.

• 한국농공학회논문집
• /
• 제57권6호
• /
• pp.163-171
• /
• 2015

This study aimed to establish a field observation system for monitoring tempo-spatially precise changes of groundwater level and to analyze the impact of rainfall and irrigation practices on groundwater changes in paddy regions. The monitoring system comprising of all nine groundwater observation wells and four ponding depth sensors was installed in a part of paddy regions benefited from Gosam reservoir, Ansung-si. The result of grundwater level change during the irrigation period in 2002 was averagely 0.51 m higher than that during the non-irrigation period. In particular between March before puddling and June after transplanting, there was maximum 1.23 m rise in groundwater level. On the other hand, concerning the change in ponding depth, groundwater level changed similarly, and hourly rainfall was revealed to have better correlation with 24-hour delayed hourly groundwater level than with the corresponding groundwater level. Eventually, this study could be referenced for further studies to set up a more comprehensive and sustainable monitoring system of groundwater conditions.

• 한국군사과학기술학회지
• /
• 제14권6호
• /
• pp.1031-1036
• /
• 2011

In this paper, we have proposed a methodology which can test and evaluate on system level in development phase of command guided missile system. Test and evaluation play a significant role in the development of weapon system, providing the means for determining to what extent the weapon system satisfies its requirements, whether it functions normally in the operational environment. In case of command guided missile having seeker, the missile communications link provides data to allow the missile to fly an efficient trajectory toward target. Therefore, it is very important to test and evaluate for data link between missile and radar on whole system aspect. we introduce the concept and devices for system level test and evaluation of command guided missile system.

• 설비공학논문집
• /
• 제19권9호
• /
• pp.622-629
• /
• 2007

Compact semi-center type automotive air handling system(AHS) is developed in this study and it's performance is compared with the conventional 3-pieces type air hand-ling system. The pressure drop is measured at component level and system level, and air flow rate and air distribution of discharge air through each ducts from air handling system are measured. System level characteristics of pressure drop at face and windshield discharge mode and air flow rate are investigated, and also temperature control linearities are tested. The volume of the air handling system package is reduced about 20%. And air flow rate increase about 5 to 20% compared to the conventional 3-pieces type air handling system at each discharge mode with significantly improved air pressure drop both component and system level. Also, air distribution and temperature controllability meet to evaluation criteria.