• Nuclear Engineering and Technology
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• 제55권3호
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• pp.919-926
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• 2023

To analyze the cause of the destruction of thin, carbon-backed lithium fluoride targets during a measurement of the fusion of ⁷Li and ¹⁷O, we estimate theoretically the lifetimes of carbon and LiF films due to sputtering, thermal evaporation, and lattice damage and compare them with the lifetime observed in the experiment. Sputtering yields and thermal evaporation rates in carbon and LiF films are too low to play significant roles in the destruction of the targets. We estimate the lifetime of the target due to lattice damage of the carbon backing and the LiF film using a previously reported model. In the experiment, elastically scattered target and beam ions were detected by surface silicon barrier (SSB) detectors so that the product of the beam flux and the target density could be monitored during the experiment. The areas of the targets exposed to different beam intensities and fluences were degraded and then perforated, forming holes with a diameter around the beam spot size. Overall, the target thickness tends to decrease linearly as a function of the beam fluence. However, the thickness also exhibits an increasing interval after SSB counts per beam ion decreases linearly, extending the target lifetime. The lifetime of thin LiF film as determined by lattice damage is calculated for the first time using a lattice damage model, and the calculated lifetime agrees well with the observed target lifetime during the experiment. In experiments using a thin LiF target to induce nuclear reactions, this study suggests methods to predict the lifetime of the LiF film and arrange the experimental plan for maximum efficiency.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.161-164
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• 2008

We proposed 2-phase regression of power function inside exponential for PDP lifetime data analysis. In introducing our method we discussed the reason why PDP degradation behavior is described by exponential function basically. By applying our method to 50HD and 50FHD PDP lifetime experiment data, we obtained more than 100,000Hr lifetime. From these results, we claim that PDP lifetime is more than 100,000Hr.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1631-1635
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• 2002

In order to be good display, the ac PDP lifetime should be guaranteed over 30000 hours. Therefore, to satisfy these demands, it is need to find out main factors in ac PDP affecting the lifetime. In this paper, the characteristics of lifetime as a parameter of the MgO deposition rate conditions is investigated. MgO protective layers is fabricated by E-beam. Before measuring the lifetime we have carefully peformed high temperature evacuation and aging procedure, which is essential for providing the initial condition of our experiment. If MgO deposition rate increased, MgO film becomes dense and an adhesive power of MgO film gets better and because occurrence rate of the MgO cluster decreases, lifetime of MgO will be improved. As a result, ac PDP lifetime can be improved due to the improvement of MgO by MgO preparation conditions.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1298-1310
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• 2019

Network coding (NC) is a promising technology that can improve available bandwidth and packet throughput in wireless sensor networks (WSNs). Sliding window is an improved technology of NC, which is a supplement of TCP/IP technology and can improve data throughput and network lifetime on WSNs. This paper proposes a network coding-based maximum lifetime algorithm for sliding window in WSNs (NC-MLSW) which improves the throughput and network lifetime in WSN. The packets on the source node are sent on the WSNs. The intermediate node encodes the received original packet and forwards the newly encoded packet to the next node. Finally, the destination node decodes the received encoded data packet and recovers the original packet. The performance of the NC-MLSW algorithm is studied using NS2 simulation software and the network packet throughput, network lifetime and data packet loss rate were evaluated. The simulations experiment results show that the NC-MLSW algorithm can obviously improve the network packet throughput and network lifetime.

• 전기전자학회논문지
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• 제18권1호
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• pp.96-105
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• 2014

본 논문에서는 배터리의 비선형적 방전 특성인 회복효과를 사용하여 배터리의 사용 시간을 연장하는 기법을 제안한다. 일반적으로 배터리의 사용 시간을 예측할 때에는 배터리 내부에 저장된 에너지가 일정하다고 가정하지만, 실제로는 배터리 내부의 화학 반응 때문에 배터리를 계속 방전시키지 않고 중간에 쉬는 시간을 만들어주면 더 많은 에너지를 끌어낼 수 있는데 이를 회복효과라 한다. 제안하는 기법에서는 다수의 배터리 셀을 교대로 방전시킴으로서 기기의 전력 공급은 그대로 유지하면서 배터리 셀 일부를 쉬게 하여 회복효과를 발생시키고, 이에 따라 배터리의 사용 시간을 연장시킬 수 있다. 실험 결과, 2개의 배터리 셀을 기존처럼 병렬 연결하여 방전시키는 것에 비해 배터리 셀을 교대로 방전시키면 배터리 사용시간이 약 7% 증가하였다.

• KSBB Journal
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• 제17권4호
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• pp.326-332
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• 2002

크로마토그래피 공정 성능 검증의 한 항목인 담체의 수명 검증을 위해 자동화된 미니 크로마토그래피 시스템(MiniValChrom)을 개발하였다. 이 시스템은 크로마토그래피공정의 자동화된 반복수행, 크로마토그래피 각 step의 작동순서 및 공정조건의 자유로운 구성, on-line 실시간 모니터링 및 제어, 여러 담체 수명 검증법의 method file 저장기능 등을 갖추었다. MiniValChrom을 사용하여 BSA와 Cibacron Blue 3G-A를 각각 모델 단백질과 담체로 담체 수명 검증실험을 사례연구로 수행하였다. 담체 수명의 감소는 크로마토그래피 공정을 반복수행하면서 5 cycle 마다 변화하는 HETP값을 측정하여 HETP 값이 1 cm 이상 될 때까지 반복 수행함으로써 담체 수명을 결정할 수 있었다. 본 연구를 통해 개발된 MiniValChrom은 다른 검증 항목이나 multi-product 생산공장 내 크로마토그래피 공정 검증에도 유용하게 쓰일 수 있을 것으로 기대된다.

• 대한임베디드공학회논문지
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• 제11권4호
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• pp.209-218
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• 2016

This paper proposes a new lifetime aware buffer mapping method of a synchronous dataflow (SDF) graph on a hybrid memory system with DRAM and PRAM. Since the number of write operations on PRAM is limited, the number of written samples on PRAM is minimized to maximize the lifetime of PRAM. We improve the utilization of DRAM by mapping more buffers on DRAM through buffer sharing. The problem is formulated formally and solved by an optimal approach of an answer set programming. In experiment, the buffer mapping method with buffer sharing improves the PRAM lifetime by 63%.

• 대한전자공학회논문지TC
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• 제46권8호
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• pp.43-49
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• 2009

본 논문에서는 에러율이 높은 무선 센서 네트워크의 수명을 연장시키기 위한 라우팅 알고리즘을 제안한다 제안하는 기법은 무선 링크의 품질을 기반으로 하여 패킷을 송수신한 이후의 잔여 에너지를 미리 추정하고, 그 때의 에너지가 가장 많이 남아 있을 것으로 예상되는 경로로 데이터를 전송한다. 제안하는 기법은 에러율을 고려하기 때문에 불필요한 재전송에 따른 에너지 소비를 줄이고 트래픽도 골고루 분산시킨다. 그리고 송수신 이후의 잔여 에너지양들 중에서 최소값이 가장 클 것으로 예상되는 경로를 선택함으로써 노드의 에너지 고갈을 최대한으로 지연시킨다. 다른 방식들에 비하여 제안하는 기법이 네트워크의 수명을 더욱 연장시킨다는 사실을 실험을 통하여 확인할 수 있었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권5호
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• pp.2469-2490
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• 2019

A low-energy adaptive clustering hierarchy (LEACH) protocol is a low-power adaptive cluster routing protocol which was proposed by MIT's Chandrakasan for sensor networks. In the LEACH protocol, the selection mode of cluster-head nodes is a random selection of cycles, which may result in uneven distribution of nodal energy and reduce the lifetime of the entire network. Hence, we propose a new selection method to enhance the lifetime of network, in this selection function, the energy consumed between nodes in the clusters and the power consumed by the transfer between the cluster head and the base station are considered at the same time. Meanwhile, the improved FTBA algorithm integrating the curve strategy is proposed to enhance local and global search capabilities. Then we combine the improved BA with LEACH, and use the intelligent algorithm to select the cluster head. Experiment results show that the improved BA has stronger optimization ability than other optimization algorithms, which the method we proposed (FTBA-TC-LEACH) is superior than the LEACH and LEACH with standard BA (SBA-LEACH). The FTBA-TC-LEACH can obviously reduce network energy consumption and enhance the lifetime of wireless sensor networks (WSNs).

• Communications for Statistical Applications and Methods
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• 제23권1호
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• pp.57-70
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• 2016

Type-II progressive censoring is one of the censoring methods frequently used in clinical studies, reliability trials, quality control of products and industrial experiments. Sometimes in Type-II progressive censoring experiments, the failure rate is low so the waiting time to observe the $m^{th}$ failure will be very long; however, the experimenter may have to terminate the experiment before a predetermined time. In this article, if two generalized types of Type-II progressive censoring are reminded, we then make some changes in the removal method of Type-II progressive censoring such that without reducing the deduction quality, the termination time of the experiment decreases. This can be done with decreasing withdraws throughout the steps of the experiment with a special reasonable method. A simulation study is done and the results are tabulated at the end of this article for a comparison between introduced method and Type-II progressive censoring.