• 상하수도학회지
• /
• 제26권3호
• /
• pp.383-397
• /
• 2012

In this study, a System Dynamics (SD) simulation model for the efficient operations of an industrial water supply system was developed by investigating the feedback loop mechanisms involved in the operations of the system. The system was modeled so that as demand is determined the water supply quantity of intake pumping stations and dams are allocated. The main feedback loop showed that many variables such as the combinations of pump operation, unit electric power(kWh/$m^3$), unit electric power costs(won/$m^3$), water level of water way tunnel, suction pressure and discharge of pumping station, and tank and service reservoir water level had causal effects and produced results depending on their causal relationship. The configurations of the model included an intake pumping station model, water way tunnel model, pumping station model (including the tank and service reservoir water level control model), and unit electric power model. The model was verified using the data from the case study industrial water supply system that consisted of a water treatment plant, two pumping stations and four dams with an annual energy costs of 5 billion won. It was shown that the electric power costs could have been saved 7~26% during the past six years if the operations had been based on the findings of this study.

• 산업공학
• /
• 제22권2호
• /
• pp.153-164
• /
• 2009

An effective management for reverse flows of products such as reuse, repair and disposal, has become an important issue for every aspect of business. In this paper, we study the Location-Routing Problem (LRP) in the multi-stage closed-loop supply chain network. The closed-loop supply chain in this study integrated both forward and reverse flows. In forward flow, a factory, Distribution Center (DC) and retailer are considered as usual. Additionally in reverse flow, we consider the Central Returns collection Center (CRC) and disposal facility. We propose a mixed integer programming model for the design of closed-loop supply chain integrating both forward and reverse flows. Since the LRP belongs to an NP-hard problem, we suggest a heuristic algorithm based on genetic algorithm. For some test problems, we found the optimal locations and routes by changing the numbers of retailers and facility candidates. Furthermore, we compare the efficiencies between open-loop and closed-loop supply chain networks. The results show that the closed-loop design is better than the open one in respect to the total routing distance and cost. This phenomenon enlarges the cut down effect on cost as an experimental space become larger.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제7권4호
• /
• pp.229-234
• /
• 2007

In this paper, we present an efficient instruction set architecture using vector register file hardware to accelerate operation of general matrix-vector operations in DSP microprocessor. The technique enables in-situ row-access as well as column access to the register files. It can reduce the number of memory access significantly. The technique is especially useful for block-based video signal processing kernels such as FFT/IFFT, DCT/IDCT, and two-dimensional filtering. We have applied the new instruction set architecture to in-loop deblocking filter processing in H.264 decoder. Performance comparisons show that the required load/store operations for the in-loop deblocking filter can be reduced about 42%. The architecture would improve the processing speed, and code density in DSP microprocessor especially for video signal processing substantially.

• 펄프종이기술
• /
• 제35권4호
• /
• pp.48-56
• /
• 2003

In this work an integrated model for paper plants combining wet-end and dry section is developed and a model predictive control scheme based on the plant model is proposed. Closed-loop process identification method is employed to produce a state-space model. Thick stock, filler flow, machine speed and steam pressure are selected as input variables and basis weight, ash content and moisture content are considered as output variables. The desired output trajectory is constructed in the form of 1st-order dynamics. Results of simulations for control of grade change operations are compared with plant operation data collected during the grade change operations under the same conditions as in simulations. From the comparison, we can see that the proposed model predictive control scheme reduces the grade change time and achieves stable steady-state.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.2600-2605
• /
• 2003

The PBL (Poly-butadiene Latex) production process is a typical batch process. Changes of the reactor characteristics due to the accumulated scaling with the increase of batch cycles require adaptive tuning of the PID controller being used. In this work we propose a tuning method for PID controllers based on the closed-loop identification and the genetic algorithm (GA) and apply it to control the PBL process. An approximated process transfer function for the PBL reactor is obtained from the closed-loop data using a suitable closed-loop identification method. Tuning is performed by GA optimization in which the objective function is given by ITAE for the setpoint change. The proposed tuning method showed good control performance in actual operations.

• 산업기술연구
• /
• 제28권B호
• /
• pp.209-214
• /
• 2008

Set-valued attributes appear in many applications to model complex objects occurring in the real world. One of the most important operations on set-valued attributes is the set join, because it provides a various method to express complex queries. Currently proposed set join algorithms are based on block nested loop join in which inverted files are partitioned horizontally into blocks. Evaluating these joins are expensive because they generate intermediate partial results severely and finally obtain the final results after merging partial results. In this paper, we present an efficient processing of set join algorithm. We propose a new set join algorithm that vertically partitions inverted files into blocks, where each block fits in memory, and performs block nested loop join without producing intermediate results. Our experiments show that the vertical bitmap nested set join algorithm outperforms previously proposed set join algorithms.

• Journal of Electrical Engineering and Technology
• /
• 제9권4호
• /
• pp.1365-1368
• /
• 2014

A CPW-fed to CPS dipole antenna of triangular loop director by microstrip tapered balun is proposed for dual and wide band operations, in this paper. The proposed antenna is consisted of a CPW-fed to CPS transform, microstrip tapered balun element, CPS dipole driver and triangular loop director. A dual and wide bandwidth of the proposed dipole antenna is realized by introducing the triangular loop director and taper matching element. The operated frequency bandwidth is 1GHz (2.14~3.14 GHz) and 1.9 GHz (4.6~6.5 GHz) to return loss criterion of less than 10 dB. The measured return loss of the proposed antenna showed good results of the dual and wide band operating frequency and the radiation pattern. The proposed antenna is able to support WLAN wireless communications applications.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1994년도 춘계공동학술대회논문집; 창원대학교; 08월 09일 Apr. 1994
• /
• pp.223-231
• /
• 1994

생산시스템 기술이 점차 확대/발전되고, 가공시스템의 고 신뢰성, 효율성 향 상에 대한 관심이 집중되면서 시스템 관련하의 다양한 분야에서 체계적인 연구가 진행되고 있다. 그중 공구관리시스템에 관해서는 지금까지 많은 연구 가 되고 있으나 단순히 재고관리 관점에서 운용되거나, 부분적으로 open-loop 상황에서 사용되고 있다. 본 연구에서는 이러한 측면에서 생산현 장에 적합하고, 공작기계와의 Interface를 고려하여 IC(Integrated Circuit)를 이용한 공구식별시스템을 구축하므로써 Manufacturing Database에서 운용되 고, 공작기계와도 공구정보를 송/수신할 수 있는 shop floor연계형 TMS(Tool Management System)를 개발하고자 한다.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
• /
• pp.723-726
• /
• 1996

본 연구에서는 액체금속로의 핵심구조인 소디움루프를 위한 운전지원 전문가시스템을 개발한다. 소디움루프는 현재 원자력연구소에서 연구 개발 단계에 있으며, 안전 운전을 위한 운전 지식을 연구하고 있는 중이다. 본 논문에서는 이러한 연구 상황에 맞추어 개발되는 전문가시스템에게 요구되는 특징을 정리하고, 소디움루프 운전의 효과적 지원과 운전원의 편의에 중점을 둔 전문가시스템의 개발을 설명한다.

• 한국국방경영분석학회지
• /
• 제25권1호
• /
• pp.37-54
• /
• 1999

In this paper, we proposed a modeling method of continuous combat simulation by using VENSIM. VENSIM is a CASE tool for developing continuous simulation. It provides a simple and flexible way of building simulation models from causal loop or influence diagram. As a case model, we developed "a prototype model of battle"incorporating infantry, artillery, air defense weapon, aircraft, and guerrilla engagement.ngagement.