• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.10a
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• pp.221-226
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• 2005

Gifford(1992, 1993, 1997, 1998)는 제한적 주의력(limited attention)의 관점에서 벤처경영자, R&D 관리자, 혁신자, 벤처 캐피탈의 의사결정을 연구하였다. 창업경영자 (entrepreneurs)는 기술 개발, 제품디자인 개발, 원자재 확보, 제품 생산, 유통채널 확보, 가격정책 결정, 판매촉진 및 마케팅정책 결정 등의 다양한 경영활동을 수행하고 끊임없이 창업기회(entrepreneurial opportunities)를 추구하는 사람이다. Gifford 는 벤처 경영자를 창업기회와 다양한 경영활동의 포트폴리오(portfolio)를 수행하고 관리하는 대리인으로 간주한 '마술사 모형(Juggler model)' 을 제시하고 이익극대화의 관점에서 대리인의 의사결정을 분석하였다. 그녀는 모형을 통하여 특정시점을 지난 기존 메뉴를 포기 하고 새로운 창업기회를 평가하는 '포기정책(discard policy)' 과 아울러 기존 메뉴를 관리한 이후 새로운 창업기회를 평가하는 '연령검사(age inspection)' 를 동시에 사용한다는 결과를 도출하였다. 본 논문은 Gifford의 마술사 모형(Juggler model)을 수정, 발전시켜 창업경영자의 의사결정을 분석하였다. Gifford의 모형은 성장하지 않는 창업기회의 포트폴리오 결정에 대한 모형이기 때문에 창업기회의 성장성이 벤처경영자의 의사결정에 어떤 영향을 미치는가에 대한 논의가 전혀 없었다. 본 논문에서는 창업경영자를 기업가적 활동을 수행하는 사람으로 정의하고 벤처경영자의 의사결정을 분석하였다. 성장률이 큰 기업에서 기업가적 활동을 수행할 때 창업경영자가 창출하는 기업의 현재가치는 크게 증가하게 되는 반면 성장률이 떨어지는 기업에서 기업가적 활동을 수행할때 창업경영자가 창출하는 기업의 현재가치는 크게 감소하게 된다. 또, 창업경영자는 성장률이 큰기업을 선택하면 관리횟수가 줄어들게 되고 이익의 감소 없이 빠르게 수확할 수가 있다. 국가의 정책과 제도가 창업경영자를 보다 성 장률이 높은 기업에서 기업가활동을 하게 한다면 국가경제의 성장속도는 빨라지게 될 것이다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.338-347
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• 2005

In this paper, a decimation-in-time search direction algorithm for displacement prediction of moving object is proposed. The initialization of the proposed algorithm for moving direction prediction is performed by detecting moving objects at sequential frames and by obtaining a moving angle and a moving distance. A moving direction of the moving object at current frame is obtained by applying the decimation-in-time search direction mask. The decimation-in-tine search direction mask is that the moving object is detected by thinning out frames among the sequential frames, and the moving direction of the moving object is predicted by the search mask which is decided by obtaining the moving angle of the moving object in the 8 directions. to examine the propriety of the proposed algorithm, velocities of a driving car are measured and tracked, and to evaluate the efficiency, the proposed algorithm is compared to the full search algorithm. The evaluated results show that the number of displacement search times is reduced up to 91.8$\%$ on the average in the proposed algorithm, and the processing time of the tracking is 32.1ms on the average.

• The KIPS Transactions:PartA
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• v.12A no.7 s.97
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• pp.571-582
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• 2005

NAND flash memory has advantages of non-volatility, little power consumption and fast access time. However, it suffers from inability that dose not provide to update-in-place and the erase cycle is limited. Moreover, the unit of read and write operations is a page. A NAND flash file system called YAFFS has been proposed. But YAFFS has several problems to be addressed. In this paper, the Reliable Flash File System(RFFS) for NAND flash memory is designed and evaluated. In designing a file system the following four issues must be considered in particular for the design: (i) to minimize a repairing time when the system fault occurs, (ii) to balance the number of block erase operations by offering wear leveling policy, and (iii) to reduce turnaround time of memory operations by reducing the amount of data written. We demonstrate and evaluate the performance of the proposed schemes.

• Journal of Digital Convergence
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• v.11 no.6
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• pp.129-135
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• 2013

With the increasing use of the SNS, WOM(Word of Mouth) has become an even more powerful and useful resource for consumers and marketers. In this paper, we investigated the effects of message polarity (positive, neutral, negative) and type (factual, evaluative) on WOM through SNS (twitter). A total of 13.4 million twitter messages were collected and 1.0 million retweeted messages were analyzed. The results showed that message orientation, type, URL and hashtag have a significant (<0.01) effect on retweet counts and the interaction between message orientation and other factors were observed. It also observed that message type, URL and hashtag have significant (0.05) relationships with retweet speed.

• Journal of Aquaculture
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• v.20 no.2
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• pp.81-84
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• 2007

We studied two research items that can be undetermined issues in the artificial seed production of the Japanese scallops, Patinopecten yessoensis, batch-specific quality of the reproductive outputs and nursery acclimation, in the embayed waters of Yangyang, Gangwon, Korea. The first batch of the spawner showed better results in terms of survival, growth, and resistance against parasitic ciliate infection over the second batch that was obtained in 5 days after first batch from the same spawner. The early attached spats directly placed in the farming ground (the unacclimated) were resistant against the water current of the open environment, by showing survival of about 80% for a month, a normal survival compared with other results. However, the spat survival during the nursery acclimation was significantly lowered in comparison with that in the unacclimated condition (P<0.01). We discussed the research results of the two items, particularly focusing on their availability for mass seed production for aquaculture in the Korean coastal waters of the East Sea (Sea of Japan).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.459-465
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• 2014

Recently, multimedia data transmission becomes important issues in the wireless sensor network. For the multimedia data transmission in wireless sensor network, QoS (Quality of service) is an important factor to determine the system performance. AODV algorithm is one of the widely used algorithm for wireless ad-hoc environment. In AODV, the destination node selects the route with the smallest hop count. Since AODV only considers the hop count, the selected route could have low channel condition, and degrade QoS. In this paper, we propose a modified AODV algorithm that considers the successful transmission rate of each link. The proposed algorithm regards the number of retransmission which can be obtained from the successful transmission rate as the hop count, and applies the modified hop count to AODV. The advantage of the proposed algorithm is that the modified AODV can support QoS without significant change of the conventional algorithm.

• Journal of the Korea Institute of Building Construction
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• v.11 no.5
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• pp.419-425
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• 2011

Topping concrete that is not reinforced with rebar to prevent poor tensile performance is vulnerable to cracking. In this study, jute, which is known to be an excellent natural fiber material for strengthening concrete performance, was compared with other cellulose fibers in terms of its capacity to reduce the cracking of concrete. As a result, it was found that compared with concrete using other fibers, concrete using jute fiber showed more than a 50 % reduction of plastic shrinkage crack resistance with the contents of 0.9 kg/$m^3$ and 1.2 kg/$m^3$ for. For impact strength tests, the final destruction of WF and PULP fibers took up to 5 times the number of falls, while jute has 10-18 circuitry, showing excellent ductility properties.

• Journal of the Korean Geotechnical Society
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• v.34 no.12
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• pp.59-69
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• 2018

In order to use the limit equilibrium theory, it is necessary to find a slip line under the ultimate failure condition. The strength reduction method using the Lagrangian finite element method defines the ultimate failure state at a time when the numerical solution cannot converge within the certain number of the iteration. When the coupled Eulerian-Lagrangian (CEL) method is used, however, such definition is inappropriate because the numerical solution of the CEL method can converge even under the ultimate failure condition. In this study, an objective condition designating the ultimate failure state in the finite element analysis adopting the CEL method was proposed. In the problem of the bearing capacity of the undrained soft ground subjected to the strip footing loading, we found that the rate of the plastic dissipated energy is highly sensitive at the load of the theoretical limit of the ultimate failure state.

• Journal of Digital Convergence
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• v.16 no.12
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• pp.593-602
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• 2018

The purpose of this study was to investigate the coloring properties of non-mordant dyes by examining local literature on silk fabric dyeing using red-colored natural dyes. Natural dyes can be prepared from the following 8 materials: purple-fleshed sweet potato, Impatiens balsamina, mulberry, fruits of Ligustrum japonicum Thunb, guava leaves, dansam, hibiscus flowers, and pruned branches of Prunus persica. To examine the surface color calculated $L^*$, $a^*$, $b^*$, ${\Delta}E^*$, and K/S value and H V/C. The variables considered in the dyeing experiment were dye concentration, dyeing temperature, dyeing time, and number of dyeing iterations, which were varied to evaluate the dyeing properties and color characteristics. As a result, the abovementioned variables, dye affinity, and red color expression were directly proportional to one another. In this study, it was found that red coloring can be obtained with natural dyes; moreover, excellent dyeing was achieved without the need for repeated dyeing or mordanting processes, which cause environmental pollution.

• Journal of Applied Biological Chemistry
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• v.65 no.1
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• pp.1-6
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• 2022

Urea is one of the most common nitrogen fertilizer, but nitrogen use efficiency by crop is low because of rapid hydrolysis of urea and loss of nitrogen in environments. Therefore, it is important to control the nitrogen release from nitrogen fertilizers. In this study, pyroligneous acid (PA) was used as a mean to inhibit urease in soil and prevent excessive nitrogen release from urea. Active ingredient in PA (AI) inhibited ammonification of urea in soil by reducing extracted ammonium nitrogen at 79.7% compared to the soil without PA. In order to evaluate the effect of PA on fertilization efficiency of urea, Chinese cabbage (Brassica campestris var. Pekinensis) was cultivated in soil treated with urea and PA both in pot and field. For PA treatment, half amount of urea was used compared to the amount of urea conventionally applied to Chinese cabbage. The PA treatment with half amount of urea resulted in similar Chinese cabbage biomass to the conventional urea application. Nitrogen concentration in Chinese cabbage was less in PA treatment indicating that Chinse cabbage effectively used nitrogen. Consequently, fertilization of urea with PA will reduce amount of fertilizer and frequency of application.