• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.11-18
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• 2010

Tool condition monitoring (TCM) is crucial for improvement of productivity in manufacturing process. However, TCM techniques have not been applied to monitor tool failure in an industrial gear shaving application. Therefore, this work studied a statistical TCM method for monitoring gear shaving tool condition. The method modeled the vibration signal of the shaving process using beta probability distribution in order to extract the effective features for TCM. Modeling includes rectifying for converting a bi-modal distribution into a unimodal distribution, estimating the parameters of beta probability distribution based on method of moments. The performance of features obtained from the proposed method was evaluated and discussed.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.337-343
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• 2002

This study deals with evaluation of bending fatigue strength in shaving gears. The saying gears were manufactured by processes that are currently used in most gears manufacturing companies. The test gears are bobbed, then the tooth surface are treated by a combination of shaving, carburizing and shot peening. The constant stress amplitude fatigue test is performed by using an electro-hydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. In this study, the effect of shaving process and shot peening was investigated and evaluated quantitatively on the fatigue strength. The enhancement of fatigue strength due to shaving process and shot peening is clarified.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.05a
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• pp.93-99
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• 2000

This study deals with the evaluation of bending fatigue strength in shaving gears, We manufactured gears using manufacture processes that are currently used in most gears manufacturing companies. The test gears are hobbed then the tooth surface are treated by a combination of shaving carbonizing and shot peening. The constant stress amplitude fatigue test is performed by using an electrohydraulic servo-controlled pulsating tester. The S-N curves are obtained and illustrated. In this study we investigated the effect of shaving process and shot peening on fatigue strength, The effect of shaving process ad shot peening on the fatigue strength is evaluated quantitatively,. The enhancement of fatigue strength due to shaving process and shot peening is clarified

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1069-1074
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• 2008

Tool condition monitoring (TCM) is crucial for improvement of productivity in manufacturing process. However, TCM techniques have not been applied to monitor tool failure in an industrial gear shaving application. Therefore, this work studied a statistical TCM method for monitoring gear shaving tool condition. The method modeled the shaving process using beta probability distribution in order to extract the effective features. Modeling includes rectifying for converting a bi-modal distribution into a unimodal distribution, estimating parameters of beta probability distribution based on method of moments. The usefulness of features obtained from the proposed method was evaluated and discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.154-157
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• 2024

최근 무선랜은 증가하는 트래픽 수요와 사용자의 다양한 애플리케이션 요구사항을 충족하기 위해 표준 기술이 진화하고 있다. 상용화가 본격적으로 시작된 WiFi 7 표준은 더 낮은 지연 시간과 더 높은 스루풋을 달성하기 위해서 멀티링크 동작(Multi-Link Operation, MLO) 기능을 도입하였다. 멀티 링크 동작은 다른 주파수 대역이나 채널을 활용하여 동시에 데이터를 송수신하는 기술로서 스루풋은 증가하지만, 전력 소모량이 커지는 문제가 있다. 또한, 종래의 무선랜 표준 기술들은 대부분 저전력의 경량 단말에서만 에너지 절감을 고려해 왔으며, AP(Access Point)의 에너지 효율성은 고려하지 않았다. 따라서 본 논문에서는 멀티링크 동작을 지원하는 AP에서 에너지 효율을 개선하는 파워 세이빙 메커니즘을 제안한다. 실험 결과에 따르면, 스루풋을 높이기 위해 링크를 산발적으로 사용하는 종래의 방식 대비 제안하는 방식의 에너지 효율성이 최대 19.18% 개선되었다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.3
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• pp.393-401
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• 2024

Recently, the Internet of Things (IoT) has been widely used in industries and daily life that directly affect human safety, life, and assets. However, IoT devices, which need to meet low-cost, lightweight, and low-power requirements, face a significant problem of shortened battery lifetime due to battery draining attacks and interference. To solve this problem, the 802.11ba standard for the Wake-up Receiver (WuR) has emerged, this feature is playing a crucial role in minimizing energy consumption. However, the WuR protocol did not consider security mechanisms in order to reduce latency and overhead. Therefore, in this study, anAdaptive Power Saving Mechanism (APSM) is proposed for low-power WuR to counter battery draining attacks. APSM can minimize abnormally occurring power consumption by exponentially increasing power-saving time in environments prone to attacks. According to experimental results, the proposed APSM improved energy consumption efficiency by a minimum of 13.77% compared to the traditional Legacy Power Saving Mechanism (LPSM) when attack traffic ratio is 10% or more of the total traffic.

• Journal of the military operations research society of Korea
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• v.33 no.2
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• pp.31-47
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• 2007

The main purpose of this study is to find out the best solution of the vehicle routing problem with hard time window by using both genetic algorithm and heuristic. A mathematical programming model was also suggested in the study. The suggested mathematical programming model gives an optimal solution by using ILOG-CPLEX. This study also suggests a hybrid genetic algorithm which considers the improvement of generation for an initial solution by savings heuristic and two heuristic processes. Two heuristic processes consists of 2-opt and Or-opt. Hybrid genetic algorithm is also compared with existing problems suggested by Solomon. We found better solutions rather than the existing genetic algorithm.

• The Magazine for Energy Service Companies
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• s.31
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• pp.28-29
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• 2004

이경희 과장은 ''용산민자역사'' 공사에서 에너지절감 설비를 책임지고 수행한 장본인이다. 그가 올해 에너지절약 유공자의 한 사람으로 지난 11월 12일 에너지절약촉진대회에서 산자부 장관상을 받은 것도 이러한 공로를 인정하고 땀방울을 격려하기 위해 그의 동료들이 적극 추천했기 때문이다. 그가 수행한 설비는 빙축열냉방시스템과 고효율 공조장비. 빙축열은 터보냉동기에 비해 연간 4억원의 절감효과를 가지고 있으며 고효율 공조장비는 연간 2억정도의 에너지세이빙효과를 가지고 있다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.129-130
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• 2015

본 논문에서는 기존의 에너지 세이빙 (Energy-Saving)을 위한 파워 모니터링 (Power Monitering) 기능을 에너지 모니터링 뿐 아니라 최신트렌드에 맞춘 생산효율 증대의 관점에서 확대 적용 가능성을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.745-747
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• 2004

배터리 파워는 모바일 애드 혹 네트워크(Mobile Ad hoc Network)에서 중요한 리소스이다. 기존의 라우팅 알고리즘에서는 노드의 파워를 on-off 시키는 방법으로 파워를 관리해왔다. 본 논문에서는 DSR (dynamic source routing)에서 route discovery, route maintenance를 할 때 각 노드의 배터리 파워 레벨을 고려하여 파워 레벨이 낮은 노드들은 RREP packet을 보내지 않음으로써 소스에서 데스티네이션까지의 경로를 오래 유지시킬 수 있고, 또한 파워 레벨이 높은 하나의 노드에 트래픽이 집중되지 않도록 하기 위해 큐(queue)에 담겨있는 트랜스미션패킷과 리시브 패킷의 수까지 고려하여 경로를 설정한다. 이 알고리즘을 이용함으로써 각 노드의 파워를 효율적으로 관리함은 물론, 전체 네트워크의 load 균형을 맞춤으로 네트워크의 수명을 길게 할 수 있다.