• 제어로봇시스템학회논문지
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• 제16권5호
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• pp.433-439
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• 2010

This paper proposes a beacon color code scheduling algorithm for the localization of multiple robots in a multi-block workspace. With the developments of intelligent robotics and ubiquitous technology, service robots are applicable for the wide area such as airports and train stations where multiple indoor GPS systems are required for the localization of the mobile robots. Indoor localization schemes using ultrasonic sensors have been widely studied due to its cheap price and high accuracy. However, ultrasonic sensors have some shortages of short transmission range and interferences with other ultrasonic signals. In order to use multiple robots in wide workspace concurrently, it is necessary to resolve the interference problem among the multiple robots in the localization process. This paper proposes an indoor localization system for concurrent multiple robots localization in a wide service area which is divided into multi-block for the reliable sensor operation. The beacon color code scheduling algorithm is developed to avoid the signal interferences and to achieve efficient localization with high accuracy and short sampling time. The performance of the proposed localization system is verified through the simulations and the real experiments.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.84.3-84
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• 2001

Suggesting the standard of optimal transferring for one RGV or two RGV, which have multiple buffers, using average delivery time and sigma in the straight line working place. For performing the optimal transferring, present RGV-Job Dispatching algorithm, which is possible to apply in realtime, and apply random job occurrence conditions for examining the possibility to apply various real environments.

• 정보저장시스템학회논문집
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• 제6권2호
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• pp.63-67
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• 2010

Holographic data storage system is one of next generation high density optical memories. Thereby storing multiple data pages using multiplexing method in one spot, we can achieve high store density and fast access time. However, for uniform writing, we must control exposure time properly by the change of writing material characteristics. Many studies have been investigated about exposure time scheduling. However, once it is decided, we cannot change the scheduled time. Therefore, it is hard to obtain uniform data intensity. In this study, we propose exposure time control method using additional red beam as the monitoring signal. Through reconstructed red beam intensity in real time, we can adjust exposure time by the writing condition change. We construct compensation method mathematically and verify the feasibility of proposed method through the experiments.

• 대한산업공학회지
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• 제42권3호
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• pp.173-181
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• 2016

This paper deals with the single-hoist and multiple-products scheduling problem. Although a mixed integer linear programming model for the problem was developed earlier, a branch-and-bound based heuristic algorithm is proposed in this paper to solve the big-size problems in real situation. The algorithm is capable of handling problems incorporating different product types, jobs in the process, and tank capacities. Using a small example problem the procedure of the heuristic algorithm is explained. To assess the performance of the heuristic we generate a bigger example problem and compare the results of the algorithm proposed in this paper with the optimal solutions derived from the mathematical model of earlier research. The comparison shows that the heuristic has very good performance and the computation time is sufficiently short to use the algorithm in real situation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권6호
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• pp.1849-1876
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• 2022

Wireless Sensor Network (WSN) is considered as an integral part of the Internet of Things (IoT) for collecting real-time data from the site having many applications in industry 4.0 and smart cities. The task of nodes is to sense the environment and send the relevant information over the internet. Though this task seems very straightforward but it is vulnerable to certain issues like energy consumption, delay, throughput, etc. To efficiently address these issues, this work develops a cross-layer model for the optimization between MAC and the Network layer of the OSI model for WSN. A high value of duty cycle for nodes is selected to control the delay and further enhances data transmission reliability. A node measurement prediction system based on the Kalman filter has been introduced, which uses the constraint based on covariance value to decide the scheduling scheme of the nodes. The concept of duty cycle for node scheduling is employed with a greedy data forwarding scheme. The proposed Duty Cycle-based Greedy Routing (DCGR) scheme aims to minimize the hop count, thereby mitigating the energy consumption rate. The proposed algorithm is tested using a real-world wastewater treatment dataset. The proposed method marks an 87.5% increase in the energy efficiency and reduction in the network latency by 61% when validated with other similar pre-existing schemes.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권6호
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• pp.286-295
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• 2006

This paper presents a design of a real-time software GPS receiver which runs on a PC. The software GPS receiver has advantages over conventional hardware based receivers in terms of flexibility and efficiency in application oriented system design and modification. In odor to reduce the processing time of the software operations in the receiver, a shared memory structure is used with a dynamic data control, and the byte-type IF data is processed through an Open Multi-Processing technique in the mixer and integrator which requires the most computational load. A high speed data acquisition device is used to capture the incoming high-rate IF signals. The FFT-IFFT correlation technique is used for initial acquisition and FLL assisted PLL is used for carrier tracking. All software modules are operated in sequence and are synchronized with pre-defined time scheduling. The performance of the designed software GPS receiver is evaluated by running it in real-time using the real GPS signals.

• 한국시뮬레이션학회논문지
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• 제11권4호
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• pp.1-14
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• 2002

This paper presents bounding space(BS) management for real-time visual simulation when using GK-DEVS models. Since GK-DEVS, extended from DEVS formalism, has information of 3D geometry and 3D hierarchical structure, we employs three types of bounding spaces: BS of its own shape, BS of its children GK-DEVS, and total BS. In addition to next-event scheduling functionality of previous GK-Simulator, its abstract simulation algorithms is extended to manage the three types of BSs so that BSs can be utilized in the rendering process of a renderer, so called GK-Renderer, We have implemented the method and evaluated it with an automated manufacturing system. In the case study, the proposed BSs management method showed about 2 times improvement in terms of rendering process speed.

• 한국정보통신학회논문지
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• 제10권8호
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• pp.1366-1372
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• 2006

농산물에 대한 수입이 개방된 이후 대량의 값싼 외국 농산물들은 점점 국내 농산물 시장의 점유율을 높이고 있으며, 이러한 과정에서 수입 시 사용된 방부제와 기타 유해 물질들의 검출 문제도 발생하고 있다. 국내 농가들은 시장 경쟁력을 높이기 위하여 국가의 체계적인 지원과 이를 뒷받침하는 시스템 도입을 요구하고 있다. 이에 본 논문에서는 소비자에게 실시간으로 농산물의 생산 및 관리 정보를 제공하기 위한 모니터링 시스템을 설계하였다. 실시간 모니터링을 위하여 기존의 CCTV(Closed-Circuit Television)와 같은 아날로그 카메라가 아니라, 장소에 구별 없이 네트워크가 가능한 곳에서 CCTV보다 좋은 화질의 영상을 제공하는 웹 카메라를 사용하여 시스템을 구현하였다. 본 실시간 모니터링 시스템의 특징은 여러 웹 카메라 영상을 다중 화면으로 구성한 멀티비전 인터페이스와 농산물을 효율적으로 관리하기 위한 영상 저장 기능 및 정해진 시간에 따라 영상 저장이 이루어지는 스케줄링 녹화가 가능하다.

• 산업경영시스템학회지
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• 제36권4호
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• pp.116-122
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• 2013

This study develops a dynamic scheduling model for parallel machine scheduling problem based on genetic algorithm (GA). GA combined with discrete event simulation to minimize the makespan and verifies the effectiveness of the developed model. This research consists of two stages. In the first stage, work sequence will be generated using GA, and the second stage developed work schedule applied to a real work area to verify that it could be executed in real work environment and remove the overlapping work, which causes bottleneck and long lead time. If not, go back to the first stage and develop another schedule until satisfied. Small size problem was experimented and suggested a reasonable schedule within limited resources. As a result of this research, work efficiency is increased, cycle time is decreased, and due date is satisfied within existed resources.

• 에너지공학
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• 제7권1호
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• pp.89-95
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• 1998

발전기의 보수계획은 전력계통의 공급신뢰도를 평가하는데 중요한 영향을 미치는 변수이다. 발전기는 반드시 검사와 보수를 해야 하기 때문에, 운전계획을 세울 때 한해의 발전기 정지계획을 고려하여 정해야 한다. 이러한 보수계획을 수립할 대에는 계절적 부하수요특징, 보수용량, 발전기 용량, 지난번 보수로부터의 경과시간 등의 여러 가지 요인들을 고려해야 한다. 본 논문에서는 발전기 보수계획 프로그램중 실용적인 방법으로 알려져 있는 LOLP(Loss of Load Probability) 평활화법을 이용하여 각 연도별 공급신뢰도를 최대로 하여 고려대상 기간 전체의 공급신뢰도를 향상시키는 보수계획 수립 알고리즘을 제안한다. 즉, 전력계통의 더 좋은 신뢰도를 얻기 위하여 전체 기간에 대한 신뢰도가 평활화되도록 보수시기를 변경하였다. 제안한 알고리즘을 실계통에 적용하여 그 유용성을 검증하였다.