• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.89-90
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• 2008

We present an implementation and it's real-sea test of an underwater acoustic communication system, which allows the system to reduce complexity and increase robustness in time variant underwater environments. For easy adaptation to complicated and time-varying environments of the ocean, all-digital transmitter and receiver systems were implemented. For frame synchronization the CAZAC sequence was used, and QPSK modulation/demodulation method with carrier frequency of 25kHz and a bandwidth of 5kHz were applied to generate 10kbps transmission rate including overhead. To improve transmission quality, we used several techniques and algorithms such as adaptive beamforming, adaptive equalizer, and convolution coding/Viterbi decoding. For the verification of the system performance, measurement of BER has been done in a very shallow water with depth of 20m at JangMok, Geoje. During the experiment, image data were successfully transmitted up to about 9.6km.

• 임상간호연구
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• 제18권2호
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• pp.228-238
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• 2012

Purpose: The purpose of this study was to examine how an Advanced Cardiac Life Support (ACLS) simulation application via smartphone effects nurses' ACLS knowledge and learning satisfaction. Methods: The participants were selected from nurses in medical Intensive Care Unit (ICU), surgical ICU and emergency room. The experimental group consists of fifty nurses who were self-learned with ACLS simulation application via smartphone and the control group of seventy-one nurses who used traditional learning materials. Outcome variables included nurses' knowledge and learning satisfaction which were collected before and after the intervention. Results: The scores of ACLS knowledge were higher in the control group compared to the experimental group (p=.001) while learning satisfaction showed no statistical difference (p=.444). In learning satisfaction, the experimental group showed higher interest than the control group (p=.019) while the control group rated higher on the item, 'the contents of education was reliable' (p=.007). Conclusion: ACLS knowledge score was graded higher in control group that used traditional learning method than the experimental group that used the smartphone application. This study showed that training with the new material significantly increased nurses' interest in ACLS education. Hence, more applications for smartphones should be developed to provide self-learning environment for nurses and improve care quality.

• JSTS:Journal of Semiconductor Technology and Science
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• 제5권4호
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• pp.221-228
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• 2005

In this work, our goal is to develop a fast and accurate power model of the ARM926EJ-S processor in the industrial design environment. Compared with existing work on processor power modeling which focuses on the power states of processor core, our model mostly focuses on the cache power model. It gives more than 93% accuracy and 1600 times speedup compared with post-layout gate-level power estimation. We also address two practical issues in applying the processor power model to the real design environment. One is to incorporate the power model into an existing commercial instruction set simulator. The other is the re-characterization of power model parameters to cope with different gate-level netlists of the processor obtained from different design teams and different fabrication technology.

• 한국지구과학회지
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• 제42권4호
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• pp.412-424
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• 2021

Understanding the distribution of heavy metals in sediment is necessary because labile heavy metals can partition into the water column and bioaccumulate in aquatic organisms. Here we investigated six heavy metals (Co, Cu, Mn, Ni, Pb, and Zn) in sediment cores using a five-step sequential leaching method to examine the occurrence of heavy metals in the sediment. The results showed that all elements, except Mn, are depleted in the exchangeable and carbonate fractions. However, heavy metal concentrations are much higher in the Fe-Mn oxide and organic matter fractions, especially for Cu, indicating enrichment in the organic matter fraction. Furthermore, contamination parameters (contamination factor and geoaccumulation index) indicate that Mn contamination is high, primarily derived from anthropogenic sources, presenting a potential risk to ecosystems in the Nakdong River.

• 제어로봇시스템학회논문지
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• 제10권1호
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• pp.87-95
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• 2004

We proposed the division algorithm that was aimed at dividing system models. It used a transitive matrix to express the relation between place and transition. And the division algorithm was applied to the scheduling problem, with the division-scheduling algorithm. The division-scheduling algorithm was able to calculate the divided subnet table. And it is able to reduce the analysis complexity. In this study, we applied the proposed division algorithm and division-scheduling algorithm to flexible manufacturing system models. We compared the efficiency and performance of the division-scheduling algorithm with the Hillion algorithm, Korbaa algorithm, and Unfolding algorithm proposed in previous researches.

• 정보저장시스템학회논문집
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• 제1권2호
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• pp.137-142
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• 2005

In this paper, we propose a new servo system design strategy to reduce the position error signal(PES) and track mis-registration(TMR) in magnetic disk drive systems. The proposed method provides a systematic design procedure based on the plant model and an optimal solution via an optimization with a 'Robust Random Neighborhood Search(RRNS)' algorithm. In addition, it guarantees the minimum PES level as well as stability to parametric uncertainties. Furthermore, the proposed method can be used to estimate the performance at the design stage and thus can reduce the cost and time for the design of the next generation product. The reduction of PES as well as robust stability is demonstrated by simulation and experiments.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.303-303
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• 2009

• Journal of Advanced Marine Engineering and Technology
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• 제31권5호
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• pp.583-591
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• 2007

This paper reports the performance of a 150W PV-wave hybrid system with battery storage in buoy. This system was originally designed to meet a new hybrid ower system for buoy in Korea. In the case or lighted buoys and lighthouses, a light failure alarm system of wireless radio is attached so that light failures are immediately notified to the office. At lighthouse offshore fixed lights and light buoys where commercial electricity is not available, the power source depends on solar system and batteries. This power system has a various problems. Therefore energy derived from the sunshine, wind and waves has been used as the energy source lot aids to navigation. Recently a hybrid system of combining the solar, wind and the wave generator is a favorable system lot the ocean facilities like lighthouse and buoy. The hybrid system in this paper is intended for variable DC load like light, communication system in the buoy and includes a PV-wane generation system and battery. This is composed a high efficiency charging algorithm, switching converter and controller. This paper includes discussion on system reliability, power quality, and effects of hybrid system in the buoy. Simulation and experimental results show excellent performance.

• KIEE International Transactions on Power Engineering
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• 제3A권3호
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• pp.124-129
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• 2003

As the power industry moves towards open competition, there has been a call for methodology to evaluate power system reliability by using composite interruption cost. This paper presents algorithms to evaluate the interruption cost of distribution power systems by taking into consideration the failure source and the composite customer interruption cost. From the consumer's standpoint, the composite customer interruption cost is considered as the most valuable index to estimate the reliability of a power distribution system. This paper presents new algorithms that take into account the load by customer type and failure probability by distribution facilities while calculating the amount of unserved energy by customer type. Finally, evaluation results of unserved energy and system interruption cost based on composite customer interruption cost are shown in detail.

• 한국한의학연구원논문집
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• 제18권3호
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• pp.141-146
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• 2012

Objectives : KIOM(Korean Institute of Oriental Medicine) built up korean medical paper database and services it through information portal OASIS. The database are updated about 1,600 papers and 48,000 references annually. Because lots of manpower and time are needed to update database, it is very important to raise up efficiency and quality of it. Methods : In this paper, we implemented web based database building system utilizing pre-built OASIS' database to improve the working process, data quality and ease of management. Results : First we designed and implemented web based system to input bibliography of the paper efficiently. It raised efficiency using OASIS' paper and reference database. Second we improved the refining process using web based system to raise up data quality. And third we developed the manager functions of web based system to control and check the working process. Conclusions : If we add korean medical dictionary and link outside paper database in the future, we hope that work efficiency and data quality will be raised more. And because the database schema of OASIS system and developed system are different, we are implementing the data transformation system.