• Journal of the Optical Society of Korea
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• v.9 no.1
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• pp.1-5
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• 2005

Using tightly focused femtosecond laser pulses, we produce an optical waveguide and optical devices in transparent materials. This technique has the potential to generate not only channel waveguides, but also three-dimensional optical devices. In this paper, an optical splitter and U-grooves, which are used for fiber alignment, are simultaneously fabricated in a fused silica glass using near-IR femtosecond laser pulses. The fiber aligned optical splitter has a low insertion loss, less than 4㏈, including an intrinsic splitting loss of 3㏈ and excess loss due to the passive alignment of a single-mode fiber. Finally, we demonstrate the utility of the femtosecond laser writing technique by fabricating gratings at the surface and inside the silica glass.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.3 no.3
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• pp.13-22
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• 1980

Research and Development has a property that involves uncertainity and risk in itself. Therefore, in order to scheduling of R & D activity, it Is needed of a certain probabilistic network technique with due regard to feedback process used to occur in the R & D proceeding. It is GERT that was developed as the need arises . In this study, the network structure of GERT-I and GERT-II was combined and then simulation analysis was used to it. According to that analysis , an advanced GERT model which covers the following stochastic problems was examined. 1 Evaluating success feasibility under the complex condition (time and cost). 2 Selecting acceptance range for the worst. 3. Selecting optimum path on basis of time, cost and success. 4. Evaluating project utility among the project alternatives. It is for managing R&D projects more effectively.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1993.06a
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• pp.1118-1120
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• 1993

Fuzzy logic places a considerable burden on an inference engine for applications such as control or approximate reasoning. Various neural network architectures have been proposed to deal with the computational task, and yet, maintain flexibility in the desired traits of the final system. Recently, we introduced a trainable network architecture whose nodes implement weighted Yager additive hybrid operators for fuzzy logic inference in an approximate reasoning setting. In this paper we examine the utility of such networks for control situations. We show that they are capable of learning control functions which are piece-wise monotonic in each of the variables. The learning ability is demonstrated through an example.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.12
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• pp.586-591
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• 2005

This paper presents a method of minimizing of generation cost on individual electrical power utility. The method is based on the Economic Dispatch (ED) and linear Available Transfer Capability (ATC). The economic dispatch redistributes the total load to individual units to minimize the generation cost without transmission network constraints. The proposed method is implemented using ATC calculated from Power Transfer Distribution Factor (PTDF) for the transmission network constraints. The performance of the proposed method has been tested for the IEEE-30 bus system. It has also been observed that the results of the proposed method is compared with that of optimal power flow.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.137-139
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• 1993

This paper details methods used to verify the adquacy of a dc traction power supply for design in Seoul matropolitain subway Line-6 system. Examples of the approach are given for a major subway presently under construction. The performance of trains operating at maximum system design capacity is modelled using a train simulation program. Using a dc network analyser program, the maximum train operating timetable, and a model of the ac and dc electrical suppy system, the electrical performance of the entire system can be modelled over a 24-hour period. The results of this analysis are used to determime: train voltage at a level sufficient to ensure train schedules: adequacy of traction transformers, rectifier, and switchgear ratings; sizes of the overhead contact systern conductors, and ac and de feeder cables: and power and energy demands at the utility company's supply points for inital and final timetable operations.

• Journal of Information Processing Systems
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• v.13 no.5
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• pp.1259-1276
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• 2017

As technologies related to sensor network are currently emerging and the use of GeoSensor is increasing along with the development of Internet of Things (IoT) technology, spatial query processing systems to efficiently process spatial sensor data are being actively studied. However, existing spatial query processing systems do not support a spatial-temporal data type and a spatial-temporal operator for processing spatialtemporal sensor data. Therefore, they are inadequate for processing spatial-temporal sensor data like GeoSensor. Accordingly, this paper developed a spatial-temporal query processing system, for efficient spatial-temporal query processing of spatial-temporal sensor data in a sensor network. Lastly, this paper verified the utility of System through a scenario, and proved that this system's performance is better than existing systems through performance assessment of performance time and memory usage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.720-722
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• 2009

Optimal operation of electric power generating plants is very essential for any power utility organization to reduce input costs and possibly the prices of electricity in general. This paper developed models for load forecasting using neural networks approach. This model is tested using actual load data of the Busan and weather data to predict the load of the Busan for one month in advance. The test results showed that the neural network forecasting approach is more suitable and efficient for a forecasting application.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.208-211
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• 2012

전력시스템에서 MDMS(Meter Data Management System)는 HAN(Home Area Network)과 Smart Meter, SUN(Smart energy Utility Network)와 같은 AMI(Advanced Metering Infrastructure) 기반 환경에서 수많은 전력 또는 수도 가스 사용량과 같은 데이터를 수집, 취득하고, 이들 데이터를 처리, 가공, 분석하여 가치 있는 정보로 변환시켜, 요금서비스 및 다양한 부가서비스 창출에 활용되는 소프트웨어 인프라이다. 최근 MDMS 개발은 기능의 중요성 뿐만 아니라 다른 응용 시스템들과의 상호 운용성을 고려하여 개발하는 요구 기능을 가진다. 본 논문에서는 스마트그리드 환경에 적합한 AMI의 전력처리시스템(MDMS) 개발을 위한 설계 방안을 기술하였다.

• Korean Journal of Remote Sensing
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• v.39 no.1
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• pp.87-97
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• 2023

Unmanned aerial vehicles (UAVs) can capture high-resolution imagery from a variety of viewing angles and altitudes; they are generally limited to collecting images of small scenes from larger regions. To improve the utility of UAV-appropriated datasetsfor use with deep learning applications, multiple datasets created from variousregions under different conditions are needed. To demonstrate a powerful new method for integrating heterogeneous UAV datasets, this paper applies a combined segmentation network (CSN) to share UAVid and semantic drone dataset encoding blocks to learn their general features, whereas its decoding blocks are trained separately on each dataset. Experimental results show that our CSN improves the accuracy of specific classes (e.g., cars), which currently comprise a low ratio in both datasets. From this result, it is expected that the range of UAV dataset utilization will increase.

• International journal of advanced smart convergence
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• v.12 no.3
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• pp.40-50
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• 2023

Blockchain is a technology designed to prevent tampering with digital documents or information, safeguarding transaction data and managing it in a structured manner. This proves beneficial in addressing issues of trust and data protection in B2B, B2C, and C2B transactions. Blockchain finds utility not only in financial transactions but also across diverse industrial sectors. This study outlines significant cases and responses that jeopardize the security of blockchain networks and cryptocurrency technology. Additionally, it analyzes safety and risk factors related to blockchain and proposes effective testing methods to preemptively counter these challenges. Furthermore, this study presents key security evaluation metrics for blockchain to ensure a balanced assessment. Additionally, it provides evaluation methods and various test case models for validating the security of blockchain and cryptocurrency transaction services, making them easily applicable to the testing process.