• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.171-178
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• 2010

Pipeline structure is one of core underground infrastructure which transports primary sources. Since the almost pipeline structures are placed underground and connected each other complexly, it is difficult to monitor their structural health condition continuously. In order to overcome this limitation of recent monitoring technique, recently, a Ubiquitous Sensor Network (USN) system based on on-line and real-time monitoring system is being developed by the authors' research group. In this study, real-time pipeline health monitoring (PHM) methodology is presented based on electromechanical impedance methods using USN. Two types of damages including loosened bolts and notches are artificially inflicted on the pipeline structures, PZT and MFC sensors that have piezoelectric characteristics are employed to detect these damages. For objective evaluation of pipeline conditions, Damage metric such as Root Mean Square Deviation (RMSD) value was computed from the impedance signals to quantify the level of the damage. Optimal threshold levels for decision making are estimated by generalized extreme value(GEV) based statistical method. Throughout a series of experimental studies, it was reviewed the effectiveness and robustness of proposed PHM system.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.274-276
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• 2006

e-seal은 RFID(Radio Frequency IDentification) 기술을 사용하여 원격에서 자동으로 봉인상태를 확인할 수 있는 컨테이너 봉인 장치를 말한다. RFID의 특징상 반도체 칩에 기록된 정보를 제 삼자가 쉽게 판독 및 변조할 수 있다는 취약점으로 인하여 활성화되지 못하고 있는 실정이다. ISO에서는 RFID의 취약점을 보안하기 위한 표준작업(ISO 18185)을 진행 중이다. 이 중, ISO 18185-4는 e-seal에 저장되는 자료나 리더와의 RF통신에서 데이터 보호를 위한 표준이다. 이와 관련된 연구로는 인증 프로토콜과 ISO 18185-4를 위한 보고서로 제출된 보안 프로토콜이 있다. 제안된 e-seal 보안 프로토콜을 적용하기 위해서는 e-seal과 리더 간의 데이터를 암/복호화할 키가 필요하지만, 키 서버를 통해 전달받은 마스터 키를 데이터 암/복호화 키로 바로 사용하는 것은 보안 상의 문제점을 야기할 수 있기 때문에 PRF(Pseudo Random Function)을 이용하여 마스터 키로부터 MTK(Mutual Transient Key)를 유도하고, MTK를 암/복호화 키로 사용해야 한다. 기존의 PRF는 일방향 해시 함수(MD5, SHA 등)를 기반으로 하는 HMAC[2. 3]을 일반적으로 사용하였다. 그러나 일방향 해시 함수는 e-seal과 같은 제한된 자원을 갖는 환경에 적합하지 않다. 따라서, 본 논문에서는 e-seal 보안 프로토콜을 위한 효율적인 PRF을 제안한다. 기존의 일방향 해시 함수 기반이 아닌 블록 암호화 알고리즘을 기반으로 하는 MAC을 이용하여 PRF을 보다 효율적으로 구현하였고, 블록 암호화 알고리즘은 AES를 선택 합성체 $GF((2^4)^2)$을 통해 하드웨어 모듈을 최적화 하였다. AES를 기반으로 하는 MAC은 HMAC에 비해 면적 및 처리율에서 뛰어난 결과를 보여주었다.<0.01).이상의 연구 결과, cook-chill생산 시 녹차 추출물의 첨가가 미생물적 품질유지에 효과가 있다고 사료되는 바 본 연구결과를 기초로 급식소에서 음식 생산 시 녹차 추출물 및 천연 항균성 물질 첨가에 따른 미생물적 품질 및 관능적 품질검사를 통한 레시피 개발에 관한 지속적인 연구가 수행되어야 하겠다.다.다리다보니 점심시간을 활용할 수 없게 되는 문제점에 대한 재검토가 필요하다. 따라서 차후 학교급식의 안전성 확보를 위한 급식환경 개선의 일환으로 식당공간 확보 시 신속한 시간 내에 급식이 가능하도록 넓은 공간과 쾌적한 환경의 식당 조성에 대해 관심을 기울여야 할 것으로 사료된다. 이상 여부를 반영하는 임상증상의 빈도가 높은 청소년기 남녀 중학생의 경우 아침과 저녁의 결식빈도 및 외식과 간식의 빈도가 높았고, 아침식사의 질과 체형만족도가 낮은 것으로 나타나 청소년의 건강과 식습관 및 체형만족도가 상호 관련성이 높은 것으로 나타났다. 따라서 본 연구 결과는 성장기 청소년의 건강 유지를 위하여 바람직한 식습관의 중요성을 재인식할 수 있었으며, 올바른 식습관 확립을 위한 영양교육의 중요성이 재확인되었다.경제적일 것으로 판단된다.er 90 % of good relative dynamic modulus of elasticity due to fineness of formation caused by the increase of the unit powder content and the improvement of flowability, without regard to the replacement of crushed stone fines. Therefore, it can be said that the usage of crushed stone fines can control the strength of super flowing concrete by replacement and re

• Journal of Service Research and Studies
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• v.9 no.2
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• pp.31-40
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• 2019

In this paper, we have studied the improvement of operational control for the enhancement of business continuity of information system becoming more important with the development of information technology such as big data, Iot, and artificial intelligence. The operational management and audit guidance of the current information system, which is coming in the fourth industrial age, where various services, data and industries are converged, is based on the existing general information system pattern and needs to be improved. The provision of services at fixed times is linked to the survival of enterprises and countries and serves as a key element. Therefore, it is necessary to study the application of optimized check items of the operation audits to minimize the service interruption damage of the information system and to provide the stable service in terms of business continuity management. To accomplish this, the check items presented in the operational control of the information system were derived by combining the PDCA step contents and 8 resource requirements provided in ISO 22301. From the point of view of increasing the business continuity according to the derivation criteria of the inspection items, the operational inspection check items were derived by exemplifying the improved check items and review items of the information system operation audit and the products to be checked during the operational audit. The check items were divided into management audit improvement check items for service continuity management, and operational audit improvement check items for performance and availability management. The average score of the IT professionals' survey on the suitability of the proposed checklist was 4.63, which was concluded to be appropriate.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.3
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• pp.75-80
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• 2002

In these days of severe struggle for existence, the world has changed a great deal to global and digital oriented period. The enterprises try to introduce new management and production system to adapt such a change. But, if the only new technologies are applied to an enterprise without definite analysis about manufacturing, failure fellows as a logical consequence. Hence, enterprise must analyze manufacturing system definitely and needs new methodologies to mitigate risk. This study suggests that the new approach, which is systems approach for process improvement, is organized to systems analysis, systems diagnosis, and systems verification. Systems analysis analyzes manufacturing systems with object-oriented methodology-UML(Unified Modeling language) from a point of product, process, and resource view. Systems diagnosis identifies the constraints to optimize the system through scientific management or TOC(Theory of constraints). Systems verification shows the solution with virtual manufacturing technique applied to the core problem which emerged from systems diagnosis. This research shows the artifacts to improve the productivity with the above methodology applied to forming shop. UML provides the definite tool for analysis and re-usability to adapt itself to environment easily. The logical tree of TOC represents logical tool to optimize the forming shop. Discrete event simulator-QUEST suggests the tool for making a decision to verify the optimized forming shop.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.668-676
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• 2012

In this paper, on the assumption that MPI collective communication function is converted into a group of point-to-point communication functions in the transaction level, an algorithm that optimizes broadcast, scatter and gather function among MPI collective communication is proposed. The MPI hardware engine that operates the proposed algorithm was designed, and it was named the OCC-MPE (Optimized Collective Communication Message Passing Engine). The OCC-MPE operates point-to-point communication by using the standard send mode. The transmission order is arranged according to the algorithm that proposes the most frequently used broadcast, scatter and gather functions among the collective communications, so the whole communication time is reduced. To measure the performance of the proposed algorithm, the OCC-MPE with the Bus Functional Model (BFM) based on SystemC was designed. After evaluating the performance through the BFM based on SystemC, the proposed OCC-MPE is designed by using VerilogHDL. As a result of synthesizing with the TSMC $0.18{\mu}m$, the gate count of each OCC-MPE is approximately 1978.95 with four processing nodes. That occupies approximately 4.15% in the whole system, which means it takes up a relatively small amount. Improved performance is expected with relatively small amounts of area increase if the OCC-MPE operated by the proposed algorithm is added to the MPSoC (Multi-Processor System on a Chip).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.8B
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• pp.637-646
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• 2012

Recently, Wireless Sensor Networks (WSNs) are used in many applications. When sensor nodes are deployed on special areas, where humans have any difficulties to get in, the nodes form network topology themselves. By using the sensor nodes, users are able to obtain environmental information. Due to the lack of the battery capability, sensor nodes should be efficiently managed with energy consumption in WSNs. In specific applications (e.g. in intrusion detections), intruders tend to occur unexpectedly. For the energy efficiency in the applications, an appropriate algorithm is strongly required. In this paper, we propose tree-based routing algorithm for the specific applications, which based on the intrusion detection. In addition, In order to decrease traffic density, the proposed algorithm provides enhanced method considering link cost and load balance, and it establishes efficient links amongst the sensor nodes. Simultaneously, by using the proposed scheme, parent and child nodes are (re-)defined. Furthermore, efficient routing table management facilitates to improve energy efficiency especially in the limited power source. In order to apply a realistic military environment, in this paper, we design three scenarios according to an intruder's moving direction; (1) the intruder is passing along a path where sensor nodes have been already deployed. (2) the intruders are crossing the path. (3) the intruders, who are moving as (1)'s scenario, are certainly deviating from the middle of the path. In conclusion, through the simulation results, we obtain the performance results in terms of latency and energy consumption, and analyze them. Finally, we validate our algorithm is highly able to adapt on such the application environments.

• Journal of Korea Society of Industrial Information Systems
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• v.19 no.5
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• pp.81-90
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• 2014

It is an element certainly required for the cost reduction of a company that forward and reverse logistics chain are unified and constitutes a resource closed-loop supply chain (CLSC). In this study, the inventory control which unifies inventory of distribution centers (DCs) of forward logistics and processing center of reverse logistics in the CLSC environment is proposed. The inventory system model for newly-constructed CLSC considers the JIT(Just-In-Time) delivery from the processing center to the manufacturer, including the making of decisions on whether to wait for the arrival of end-of-life products or to back-order necessary products for manufacturer when the supply of end-of-life products at the processing center via the returning center is insufficient for the demands of the manufacturers. The validity of the proposed model was verified using the genetic algorithm (GA). In order that a parameter might investigate the effect which it has on a solution, the simulation was carried out for priGA(priority-based GA) on three kinds of parameter conditions. Moreover, mhGA(modified hybrid GA) to which a parameter is adjusted for every Study on Reducing Logistics Costs and Inventory Control System according to facilities integration in the Closed-Loop Supply Chain Environment generation, the simulation was carried out to a four-kind numerical example.

• Journal of Korean Society of Forest Science
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• v.98 no.1
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• pp.125-131
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• 2009

To facilitate the sustainable forest management, Forest Service in Korea has assigned 2.9 million hectare forests as 'intensive management forests' and encouraged local governments to develop a strategic management plan for their forests. One of problems for the sustainable forest management in Korea is the skewed distribution of forest age classes. Currently the majority of forestlands in Korea is occupied by age classes III and IV. In this study, we intended to find an optimum harvest volume, which enable one to make the intensive management forest in Youngdong-Gun evenly distributed for the age classes and allow an even harvest volume through a 50 year time horizon. To develop an optimization model, we applied the goal programming technique which is adequate for a multi-purpose management planning. The results indicated that it is necessary to harvest 1.2 million cubic meters in each decade to achieve the most stable distribution of age classes for the study site. The harvest volume target resulted from this study would be used in a management planning or an associated policy making process in the future.

• Journal of KIISE:Information Networking
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• v.29 no.4
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• pp.447-458
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• 2002

In this paper, we design and implement Wireless Transaction Protocol(WTP) and evaluate it for wireless transaction processing in mobile computing environments. The design and implementation of WTP are based on the coroutine model that might be suitable for light-weight portable devices. We test the compatibility between our product and the other products such as Nokia, Kannel and WinWAP For the evaluation of WTP, we use an Internet simulator that can arbitrary generate random wireless errors based on the Gilbert model. In our experiment, the performance of WTP is measured and compared to those of Transmission Control Protocol(TCP) and TCP for Transactions. The experiment shows that WTP outperforms the other two protocols for wireless transaction processing in terms of throughput and delay. Especially, WTP shows much higher performance In ease of high error rate and high probability of burst errors. This comes from the fact that WTP uses a small number of packets to process a transaction compared to the other two protocols and introduces a fixed time interval for retransmission instead of the exponential backoff algorithm. The experiment also shows that the WTP performance is optimized when the retransmission counter is set to 5 or 6 in case of high burst error rate.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.1
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• pp.1-6
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• 2017

Recent researches on radio frequency energy harvesting networks(RF-EHNs) with limited energy resource like battery have been focusing on the development of a new scheme that can effectively extend the whole lifetime of a network to semipermanent. In order for considerable increase both in the amount of energy obtained from radio frequency energy harvesting and its charging effectiveness, it is very important to design a network that supports energy harvesting and data transfer simultaneously with the full consideration of various characteristics affecting the performance of a RF-EHN. In this paper, we proposes an interference-based charging aware routing protocol(ICARP) that utilizes interference information and charging time to maximize the amount of energy harvesting and to minimize the end-to-end delay from a source to the given destination node. To accomplish the research objectives, this paper gives a design of ICARP adopting new network metrics such as interference information and charging time to minimize end-to-end delay in energy harvesting wireless networks. The proposed method enables a RF-EHN to reduce the number of packet losses and retransmissions significantly for better energy consumption. Finally, simulation results show that the network performance in the aspects of packet transmission rate and end-to-end delay has enhanced with the comparison of existing routing protocols.