• Journal of Information Processing Systems
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• 제13권6호
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• pp.1544-1553
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• 2017

The network coding mechanism has attracted much attention because of its advantage of enhanced network throughput which is a desirable characteristic especially in a multi-hop wireless network with limited link capacity such as the device-to-device (D2D) communication network of 5G. COPE proposes to use the XOR-based network coding in the two-hop wireless network topology. For multi-hop wireless networks, the Distributed Coding-Aware Routing (DCAR) mechanism was proposed, in which the coding conditions for two flows intersecting at an intermediate node are defined and the routing metric to improve the coding opportunity by preferring those routes with longer queues is designed. Because the routes with longer queues may increase the delay, DCAR is inefficient in delivering real-time multimedia traffic flows. In this paper, we propose a network coding-aware routing protocol for multi-hop wireless networks that enhances DCAR by considering traffic load distribution and link quality. From this, we can achieve higher network throughput and lower end-to-end delay at the same time for the proper delivery of time-sensitive data flow. The Qualnet-based simulation results show that our proposed scheme outperforms DCAR in terms of throughput and delay.

• 한국치위생학회지
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• 제4권1호
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• pp.119-132
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• 2004

The purpose of this study was to introduce PBL to dental hygienist education in an effort to raise a question about the inauthentic and inappropriate curriculum. PBL is one of learning methods to enhance the problem-solving ability of learners, and it's attempted to develop a PBL package focusing on dental hygienist roles to lay the foundation for producing competent and expert dental hygienists with a good problem- solving ability. The literature concerned was reviewed from November 2002 through January 2003 to determine whether or not PBL was applicable to dental-hygienist course, and that turned out to be effective for dental hygienist education. And then a PBL package was developed to train students to be knowledgeable and have a knowhow and excellent problem-solving skills. The characteristics of the PBL package could be described as follows: First, that focused on dental hygienist roles to serve the purpose of this study to remedy the current unrealistic and improper curriculum and improve the problem-solving skills of learners. Second, time factor was taken into account. In this four-week course for two credits, there are four classes a week, and it's required to take six or eight weeks to apply the PBL package, which is expected to demotivate students. Therefore, it's planned to conduct more weekly classes to make a proper progress. Third, a wide variety of teaching aids were put to use, and learner would be encouraged to be more interactive and utilize teaching aids properly, and eventually, they could have an opportunity to better express themselves. Fourth, online real-time learner discussion would be attended by this researcher. Learners would have a discussion in real time in the Internet cafe chat room, and different discussion time would be allocated to each team. This researcher would take part in each team's discussion once or more. Fifth, learners would prepare one or more journal(s) about four-hour Internet cafe learning. They have to make it twice a week at least, and it would be a good opportunity for learners to look back on themselves and their teams, and their learning effect would be greater. Specific rules were presented to help them make a successful self-examination. Sixth, there are some spaces in the lower part of objective test sheets to have students describe why they make a particular answer choice. They would be asked to depict the reason of their prior evaluation and lecture assessment especially because their responses would be important for more successful discussion and feedback. Seventh, problem-solving approach was designed to attain learning objectives, stimulate the creative thinking of learners and help them share a more systematic discussion. That would serve as a secondhand guide not to make them digress when they discuss by using information they acquire from a scenario presented in class.

• Journal of the korean society of oceanography
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• 제31권4호
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• pp.164-172
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• 1996

CREAMS (Circulation Research of the East Asian Marginal Seas) Expeditions have provided a rare opportunity to carry out precise measurements of salinity, temperature and chemical tracers extensively in all major basins of the East Sea (Japan Sea) in 1993-1996 for the first time in more than 60 years since Uda's investigation (Uda, 1934). Studies revealed unequivocal evidence that the East Sea Proper Water (ESPW), previously known as a single homogeneous water mass, is indeed made of several distinct water masses. CREAMS data further confirmed the earlier observations of Gamo et al. (1986) that properties in Deep Waters in the East Sea have been changing during at least the last 25 years. There is evidence, especially from the analysis of the DO profile, that these changes may result from a major change in the mode of deep water formation: from bottom water formation in the past to intermediate/deep water formation in recent years. The causes for these changes are not clear at the present time, but nay include natural variation and may also reflect recent global changes in regional scale. A moving-boundary box model is presented to describe current observations, predicting the turnover time of the total deep and bottom waters to the cold surface waters to be ${\sim}$80 years in 1996.

• Animal Systematics, Evolution and Diversity
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• 제24권3호
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• pp.327-332
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• 2008

Soft coral Dendronephthya gigantea (Verrill, 1864) is a conspicuous species dominating shallow sea waters of Jejudo Island, Korea. Recently its whole mitochondrial genome sequencing was completed by us and the sequence information provided an opportunity to test the age of Octocorallia and time of evolutionary separation between some representative orders of the subclass Octocorallia. Molecular phylogenetic analyses based on 13 mitochondrial protein encoding genes revealed a polyphyletic relationship among octocorallians representing two orders (Alcyonacea and Gorgonacea) and four families (Alcyoniidae, Nephtheidae, Briareidae, and Gorgoniidae). Estimates of divergence times among octocorallians indicate that the first splitting might occur around end of or after Cretaceous period (50-79 million years ago (Ma)). The age is relatively young compared to the long history of stony sea corals (>240 Ma). Taken together our result suggests a possible relatively recent radiating evolution at least in the order Alcyonacea and Gorgonacea. Molecular dating and phylogenetic analysis based on much broader taxon sampling and many genes might give an insight into this interesting hypothesis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3470-3493
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• 2019

IEEE 802.11s-based infrastructure Wireless Mesh Networks (iWMNs) are envisaged as a promising solution to provide ubiquitous wireless Internet access. The limited network capacity is a problem mainly caused by the medium contention between mesh users and the mesh access points (MAPs), which gets worst when the mesh clients employ the Transmission Control Protocol (TCP). To mitigate this problem, we use wireless network coding (WNC) in the MAPs. The aim of this proposal is to take advantage of the network topology around the MAPs, to alleviate the contention and maximize the use of the network capacity. We evaluate WNC when is used in MAPs. We model the formation of coding opportunities and, using computer simulations, we evaluate the formation of such coding opportunities. The results show that as the users density grows, the coding opportunities increase up to 70%; however, at the same time, the coding delay increments significantly. In order to reduce such delay, we propose to adaptively adjust the time that a packet can wait to catch a coding opportunity in an MAP. We assess the performance of moving-average estimation methods to forecast this adaptive sojourn time. We show that using moving-average estimation methods can significantly decrease the coding delay since they consider the traffic density conditions.

• Journal of information and communication convergence engineering
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• 제22권2호
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• pp.109-120
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• 2024

Trash or garbage is one of the most dangerous health and environmental problems that affect pollution. Pollution affects nature, human life, and wildlife. In this paper, we propose modern solutions for cleaning the environment of trash pollution by enforcing strict action against people who dump trash inappropriately on streets, outside the home, and in unnecessary places. Artificial Intelligence (AI), especially Deep Learning (DL), has been used to automate and solve issues in the world. We availed this as an excellent opportunity to develop a system that identifies trash using a deep convolutional neural network (CNN). This paper proposes a real-time garbage identification system based on a deep CNN architecture with eight distinct classes for the training dataset. After identifying the garbage, the CCTV camera captures a video of the individual placing the trash in the incorrect location and sends an alert notice to the relevant authority.

• 대한지구과학교육학회지
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• 제7권2호
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• pp.169-179
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• 2014

The purpose of this study is to research about the effects on improvement academic achievement of students based on the core learning standards of science. The researcher selected experimenter and started this study as a graduate student who is majoring in science education, experimenter chose to study 48 Sixth graders in elementary schools in B city for research group(24 students), Comparison group(24 students). The study was conducted from March to the end of July 2014. The teacher who is doing activity of professor in research group and the comparison group is science education specialist. Researcher and experimenter frequently exchange their opinions for control variables of teacher. The results are as follows. First, based on unit time strategies based on core achievement standards classes are effective in improving students' academic achievement. Elementary school teacher has difficulty in teaching for all subjects based on unit time strategies. Second, based on unit time strategies based on core achievement standards classes showed high level of satisfaction in perception of students. Thus it can be seen that teaching strategies of unit time based on the core achievement standards is effective to academic achievement improvement. The proposal for further study based on the results is as follows. First, research is needed to study the teaching methods that have practical and theoretical study time and lesson application opportunity for teaching strategies of curriculum unit time. Second, experimental studies that using strategies of unit time based on the core achievement standards are needed about learning method that can be applied in a variety of subjects.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권9호
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• pp.1492-1512
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• 2011

Due to multiple hops, mobility and time-varying channel, supporting delay sensitive real-time traffic in wireless local area network-based (WLAN) mesh networks is a challenging task. In particular for real-time traffic subject to medium access control (MAC) layer control overhead, such as preamble, carrier sense waiting time and the random backoff period, the performance of real-time flows will be degraded greatly. In order to support real-time traffic, an efficient adaptive packet scheduling (APS) scheme is proposed, which aims to improve the system performance by guaranteeing inter-class, intra-class service differentiation and adaptively adjusting the packet length. APS classifies incoming packets by the IEEE 802.11e access class and then queued into a suitable buffer queue. APS employs strict priority service discipline for resource allocation among different service classes to achieve inter-class fairness. By estimating the received signal to interference plus noise ratio (SINR) per bit and current link condition, APS is able to calculate the optimized packet length with bi-dimensional markov MAC model to improve system performance. To achieve the fairness of intra-class, APS also takes maximum tolerable packet delay, transmission requests, and average allocation transmission into consideration to allocate transmission opportunity to the corresponding traffic. Detailed simulation results and comparison with IEEE 802.11e enhanced distributed channel access (EDCA) scheme show that the proposed APS scheme is able to effectively provide inter-class and intra-class differentiate services and improve QoS for real-time traffic in terms of throughput, end-to-end delay, packet loss rate and fairness.

• 기업가정신과 벤처연구
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• 제19권4호
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• pp.19-39
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• 2016

제품의 복잡성이 증대될수록 기업의 전략은 나홀로(stand-alone)전략과 경쟁중심 전략에서 기업생태계 전략과 협력전략으로 이행할 필요성이 높아진다. 기업의 상생경영 및 동반성장이란 기업생태계 협력전략을 통해 대기업과 협력기업간의 기업건강성을 추구하여 장기적으로 지속가능한 성장을 하기 위한 노력이다. 본 연구는 기업 간 상생경영 및 동반성장 전략을 통해 기업생태계가 건강해질 수 있다는 이론적 명제를 삼성전자 협력업체의 사례분석과 종단적 자료에 기반한 추세분석을 통해 검증해보고자 한 것이다. 특히 본 연구에서는 중소기업생태계의 취약점의 하나인 글로벌화와 해외시장개척의 정도를 주요한 성과척도로 활용하였다. 왜냐하면 한국중소기업들이 연구개발과 창조성노력이 해외시장개척으로 연결되지 못하고 있는 연구개발 패러독스에 빠져있는 경우가 많기 때문이다. 그러므로 해외시장 개척없이는 기업생태계의 건강성 유지가 어려우며, 협력기업들은 글로벌 시장개척여부가 강소기업으로 가는 진화경로의 핵심이기 때문이다. 이를 위해 기업생태계 건강성의 특성을 나타내는 COPP 모델의 4대요소를 중심으로 분석하였다. COPP 모델이란 창조성(Creativity), 시장성(Opportunity), 생산성(Productivity), 그리고 선제적 대응성(Proactivity)이 선순환 해야 기업생태계의 지속가능성장이 만들어 질 수 있다는 것이다. 선제적 대응성(Proactivity) 이란 현재 만들어진 이익을 미래환경변화에 미래 선제적으로 투자하려는 기업가정신의 발로이며, 이러한 미래투자 없이는 현재의 저주(Curse of Incumbency)를 극복하기 어렵기 때문이다. 이 모델을 중심으로 삼성전자 동반성장의 주요 성과를 살펴보면 다음과 같다. 첫째, 시장성이 창조성, 생산성, 그리고 수익창출의 매개변수가 되고 있음을 발견 하였다. 즉, 수출(시장성)하는 협력기업일수록 연구개발투자(창조성)가 기업의 생산성, 수익성으로 연결되고 있었다. 반면 수출을 하지 않는 협력업체일수록 연구개발투자가 수익 성과로 연결되지 않는다는 것을 발견하였다. 둘째, 창조성, 시장성, 생산성, 미래 선제적 대응성의 순환 구조에 있어서, 선제적 대응성의 결과인 미래를 위한 연구개발비 투자를 많이 할수록(선제적 대응성) 특허를 많이 등록(창조성)하고, 특허를 많이 등록한 기업은 수출을 많이 하고(시장성), 수출을 많이 하는 기업은 영업이익(생산성, 수익성)이 높다는 것을 발견할 수 있었다. 이제 중소기업은 글로벌시장에 진출할 수 있는 경쟁력 보완 없이 지속적인 성장은 어렵다. 본 연구의 결과, 미래를 위한 투자인 선제적 대응성이 높은 기업일수록 창조성-시장성-생산성의 선순환이 이루어지고, 이것이 글로벌강소기업으로 진화하는 길임을 보여주는 전략적 시사점을 얻을 수 있었다.

• 한국축산시설환경학회지
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• 제3권1호
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• pp.49-56
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• 1997

Most of Korean broiler farms are constructed with vinyl houses. Such types of broiler farms might be cheaper in terms of cost, but poor in terms of environment condition. According to enlargement of broiler farm size, high value production systems or automatic facilities are introduced in this field. However, investment may not always guarantee the profit of the management. Therefore, it is necessary to undertake the investment analysis before decision making for the investment. Under the assumption that 870 Pyoung(≒$3.3㎡) of a broiler farm within 1,740 Pyoung(≒3.3㎡) of land is built with the producing capacity of 50,000 heads of chicken in a time. The total investment is calculated to be 600 million won(1,000 won≒$1.1), and out of them 58.1% is provided by the owner, 31.6% from the government loan, 5.8% from government subsidy, and 5.3% from other agencies or banks. The expected profit of the broiler farm is 64.6 million won(1,000 won≒$1.1) per year. The IRR calculated is 0.0808 which means that the rate to profit of this project would be 8.1%. This also means that for this investment the interest rate of the capital provided should be less than 8.1% per year. Considering that the current opportunity cost of the own capital is 8.5% this project is not so attractive for those who is going to build broiler farms mainly with their own capital. In other words this project would not be profitable, unless the average interest rate of the loans provided for this project is less than 8.1% per year.