• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2013년도 전력전자학술대회 논문집
• /
• pp.447-448
• /
• 2013

This paper investigates a new approach based on the fuzzy-logic controlled methodology that is suitable for analyzing and evaluating large format $LiMn_2O_4$ cell performance via online state-of-health (SOH) estimation for energy storage system (ESS) applications. First of all, the values of the cell resistance R and maximum cell capacity $Q_{max}$ are calculated from three factors such as voltage, current, and time that were measured by discharging/charging sequence. Then, using two values R and $Q_{max}$ previously calculated, present SOH of an arbitrary $LiMn_2O_4$ cell can be estimated using the defined fuzzy-logic inference system. The main advantage of this approach is wide parameters tuning possibility for good correspondence of SOH decay with other accurate estimation method and the possibility to perform suitable online SOH estimation.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 추계학술대회 논문집
• /
• pp.712-719
• /
• 2000

This paper presents a new algorithm to analyze a train voltages of multi-trains in auto-transformer-fed AC railway systems, using electrical equivalent change. The train current will be divided into circulation and return currents, and these current values are the same. By evaluating each current independently, the result will be more precise. The train current flows through the all auto-transformer corresponding to track impedance. In analyzing the railway system, the algorithm is based on the K.C.L, K.V.L, superposition and circuit separation method. Multi-train's voltages are determined by calculating the catenary voltage at each train's position and adding up these train's voltage drop. Case studies use a field operational data, show that tile proposed method is easily applied.

• 디지털융복합연구
• /
• 제11권5호
• /
• pp.105-117
• /
• 2013

소프트웨어의 품질을 바라보는 관점이 다양한 특성으로 나타날 수 있으나, 소프트웨어의 내부적인 면에는 관심이 없는 엔드유저 입장에서는 소프트웨어의 사용자 인터페이스(User Interface)가 소프트웨어의 품질을 표현하는 전부일 수도 있다. 그러나 사용자 인터페이스에 기반을 둔 상세화된 평가기준은 다소 미흡한 실정이므로 소프트웨어의 사용자 인터페이스는 사용성 품질 특성의 주요 대상이라 할 수 있다. 본 논문에서는 소프트웨어의 품질평가에 관련된 국제표준의 품질특성들과 사용자 인터페이스를 구성하는 요소들과의 관련성을 명확히 분석하여 소프트웨어의 사용자 인터페이스로부터 측정할 수 있는 품질특성 요소들을 추출하고 평가하는 방법에 대한 체계를 구축하였다.

• International Journal of Advanced Culture Technology
• /
• 제3권2호
• /
• pp.1-14
• /
• 2015

The purpose of this paper is to reveal two problems in the existing inventory systems in retail market, and to suggest a Two-Bin System under Automatic Ordering System considering only base-stock. Large retailers already have a sophisticated inventory system based on an automatic ordering principle. However, why does the out-of-stock (OOS) happen in large discount stores in spite of having a good inventory system? This paper suggests two systems after finding the root causes concerning the previous question. For evaluating the performance of each system, the random 200 data set in each sample group was generated from MINITAB 16 and obeyed the Poisson distribution. The existing inventory system in retail market cannot help generating OOS due to indwelling contradiction in itself. The reasons are the ordering deadline and the relationship between ordering quantity and base stock. This paper also demonstrates that these previous studies on inventory fall into the closed loop. Also the paper shows that the performance of the replenishment policy was better than traditional methods dealing with ordering quantity and base stock.

• Nuclear Engineering and Technology
• /
• 제41권6호
• /
• pp.785-796
• /
• 2009

A KALIMER-600 concept which is a type of sodium-cooled fast reactor, has been developed at KAERI. It uses sodium as a primary coolant and is a pool-type reactor to enhance safety. Also, a supercritical carbon dioxide ($CO_2$) Brayton cycle is considered as an alternative to an energy conversion system to eliminate the sodium water reaction and to improve efficiency. In this study, a simplified model for analyzing the thermodynamic performance of the KALIMER-600 coupled with a supercritical $CO_2$ Brayton cycle was developed. To develop the analysis model, a commercial modular modeling system (MMS) was adopted as a base engine, which was developed by nHance Technology in USA. It has a convenient graphical user interface and many component modules to model the plant. A new user library for thermodynamic properties of sodium and supercritical $CO_2$ was developed and attached to the MMS. In addition, some component modules in the MMS were modified to be appropriate for analysis of the KALIMER-600 coupled with the supercritical $CO_2$ cycle. Then, a simplified performance analysis code was developed by modeling the KALIMER-600 plant with the modified MMS. After evaluating the developed code with each component data and a steady state of the plant, a simple power reduction and recovery event was evaluated. The results showed an achievable capability for a performance analysis code. The developed code will be used to develop the operational strategy and some control logics for the operation of the KALIMER-600 with a supercritical $CO_2$ Brayton cycle after further studies of analyzing various operational events.

• 한국태양에너지학회 논문집
• /
• 제24권2호
• /
• pp.9-15
• /
• 2004

3kW grid connected PV(photovoltaic) systems have been constructed for evaluating and analyzing performance of PV system at FDTC(field demonstration test center) in Korea, PV systems installed in FDTC have been operating and monitored since November 2002. As climatic and irradiation conditions have been varied through long-term field test, data acquisition system has been constructed for measuring performance of PV system to observe the overall effect of environmental conditions on their operation characteristics. The performance of PV systems has been evaluated and analyzed for component perspective(PV array and power conditioning system) and global perspective(system efficiency, capacity factor, and electrical power energy) by field test. By the results, it is very important to develop optimal design technology of grid connected PV system.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1999년도 추계학술대회 논문집
• /
• pp.63-69
• /
• 1999

The research trend of the simulation optimization has been focused on exploring continuous decision variables. Yet, the research in discrete decision variable area has not been fully studied. A new research trend for optimizing discrete decision variables ha just appeared recently. This study, therefore, deals with a discrete simulation method to get the system evaluation criteria required for designing a complex probabilistic discrete event system and to search the effective and reliable alternatives to satisfy the objective values of the given system through a on-line, single run with the short time period. Finding the alternative, we construct an algorithm which changes values of decision variables and a design alternative by using the stopping algorithm which ends the simulation in a steady state of system. To avoid the loss of data while analyzing the acquired design alternative in the steady state, we provide background for estimation of an auto-regressive model and mean and confidence interval for evaluating correctly the objective function obtained by small amount of output data through simulation with the short time period. In numerical experiment we applied the proposed algorithm to (s, S) inventory system problem with varying Δt value. In case of the (s, S) inventory system, we obtained good design alternative when Δt value is larger than 100.

• 한국건설관리학회논문집
• /
• 제1권3호
• /
• pp.89-100
• /
• 2000

본 논문은 건설 감리 수행시 영향을 미치는 계층적 관리요소를 분석하여 감리사업 평가 모델을 구축함으로써 감리 프로젝트 수행시의 효율을 극대화시키는데 그 목적이 있다. 연구는 현장 실무자에 대한 설문조사를 통해 감리사업의 현황과 영향요소를 산정하였고, 이를 바탕으로 현장 감리자의 운영 및 관리능력을 평가할 수 있는 평가 모델을 구축하였다. 이러한 평가도구를 감리사업의 의사결정 및 평가 프로세스에 반영하여 전반적인 사업관리상의 효율을 증대시킬 수 있다.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 1996년도 The Korean Institute of Navigation 1996년도 춘계학술발표회 논문집
• /
• pp.77-92
• /
• 1996

When an automatic course-keeping is concerned as is quite popular in modern navigation the closed-loop steering system consists of autopilot device power unit (or telemotor unit) steering gear magnetic or gyro compass and ship dynamics. The consideration of irregular disturbances to ship dyanmics and a few non-linear mechanisms involved in the system inevitably or artificially are known to be very important in properly evaluating or analyzing the automatic steering system. In the present study the mathematical model of each element of an automatic steering system is derived which takes account of a fex non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. The calculation method of imposing irregular disturbances to ship dynamics is proposed where irregular disturbances implying irregular wave and the fluctuating component of wind. For he evaluation of automatic steering system of ships in the open seas an important term "performance index" is introduced from the viewpoint of energy saving which derived from the concept of energy loss on ship propulsion. Finally the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of linear and/or non-linear control constants of autopilot on propulsive energy loss are investigated to validate and clarify the present smulation technique.

• 융합보안논문지
• /
• 제20권4호
• /
• pp.35-45
• /
• 2020

최첨단 자산인 항공무기체계에 대한 사이버공격이 현실화되고 지속적인 위협으로 다가오고 있다. 그러나 현재 항공무기체계의 내장형 소프트웨어 특성상 평시 네트워크와 연결성 없이 관리되고 운용되어지고 있어 상대적으로 사이버공격에 대한 대응 관리가 취약한 실정이다. 따라서 사이버공격이 현실화 되었을 경우 그러한 공격이 항공임무명령서(ATO: Air Tasking Order) 수행에 미칠 악영향에 대한 평가방안과 대비가 절실하다. 본 논문에서는 항공무기체계에 대한 사이버공격이 발생할 경우 이에 대한 ATO수행의 혼란을 피하고 체계적인 대응을 위하여 작전영향성평가 프레임워크를 제안한다. 제안된 프레임워크는 항공무기체계 시스템별로 항공작전에 미치는 영향을 분석하고 이를 위한 대응조치들을 표준화함으로써 무경고하에 발생할 수 있는 사이버공격에 대하여 작전에 미치는 부정적 영향을 최소화할 수 있도록 설계되었다. 그리고 작전 지휘관이 사이버공격이 발생하는 상황 하에서도 작전수행을 위한 신속한 지휘결심을 할 수 있도록 지원한다.