• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1472-1480
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• 2016

When disasters such as earthquake, flood, typhoon, fire and terrorism are occurred a video management system is required which can shoot video on the disaster site, and send it to a server located in the command center that can grasp at a glance the site conditions. In this paper, to know the performance elements information needed to construct the video management system. we presented a method of configuring an ad hoc network based on Wi-Fi direct communication. And we also evaluated the performance through built of environment for the video management system. The evaluated performance test items are 'packet flow tests according to the video compression ratios and the image sizes', 'packet flow tests according to the distance and traffic tests', 'packet flow tests according to whether LOS or not', and 'performance test of scenarios'.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.79-85
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• 2016

Network traffic is increased rapidly, due to mobile and social network, such as smartphones and facebook, in recent web environment. In this paper, we improved web response time of existing system using direct buffer of NIO and DMA. This solved the disadvantage of JAVA, such as CPU performance reduction due to the blocking of I/O, garbage collection of buffer. Key values circulated many data due to priority change put on a hash map operated easily and apply a priority modification algorithm. Large response data is separated and stored at a fast direct buffer and improved performance. This paper showed that the proposed method using NIO was much improved performance, in many test situations of cache hit and cache miss.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.4
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• pp.1976-1981
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• 2013

In this paper, we propose a frequency-domain interference cancellation algorithm for direct-sequence spread spectrum systems. In the previously proposed frequency-domain interference cancellation algorithms that protocol defines the rules concerning the collection of means of Transmission Control Protocol (TCP: Transmission Control Protocol) is the most widely used in the transport layer. Two-way traffic through the network path to the same end-to-end transfer of data in the opposite direction between pairs of nodes are infused with two or more TCP connection using the network traffic patterns from the exchanger and routers share results of approval. Per-flow input/output structure of matter using the LTS online reaction when evaluated as this is the most important factor. TCP-MT when the connection duration is one of the largest performance gains.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1161-1168
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• 2018

On April 27 2018, North-South Korea agreed to establish the practical methods for connecting the railway in the inter-Korean summit talks. This is often reported that the train will be operated directly between Busan and Europe. However, there are many problems for the railway to directly connect between Busan and Europe. Because a train from Busan to Europe should pass through North Korea, China or Russia, and each national railway systems are different. Thus, South Korean railway has to study thoroughly an interoperability before railways directly operates between a nation and another. The standards and technical harmony for direct connection with a different railway network is very important, because a rail transport is a total network system. This paper surveyed a European railway interoperability and studied on the basic direct operation for the North-South Korean railway systems.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.1
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• pp.111-118
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• 2004

In this paper, we present a novel approach for the structure of Fuzzy Neural Network(FNN) based on wavelet function and apply this network structure to the solution of the tracking problem for mobile robots. Generally, the wavelet fuzzy model(WFM) has the advantage of the wavelet transform by constituting the fuzzy basis function(FBF) and the conclusion part to equalize the linear combination of FBF with the linear combination of wavelet functions. However, it is very difficult to identify the fuzzy rules and to tune the membership functions of the fuzzy reasoning mechanism. Neural networks, on the other hand, utilize their learning capability for automatic identification and tuning. Therefore, we design a wavelet based FNN structure(WFNN) that merges these advantages of neural network, fuzzy model and wavelet transform. The basic idea of our wavelet based FNN is to realize the process of fuzzy reasoning of wavelet fuzzy system by the structure of a neural network and to make the parameters of fuzzy reasoning be expressed by the connection weights of a neural network. And our network can automatically identify the fuzzy rules by modifying the connection weights of the networks via the gradient descent scheme. To verify the efficiency of our network structure, we evaluate the tracking performance for mobile robot and compare it with those of the FNN and the WFM.

• Journal of Families and Better Life
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• v.27 no.5
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• pp.91-99
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• 2009

This study investigates the relationships among emotional support from social network, ego-resiliency, and role conflict of teachers in kindergartens and day care centers. The subjects were 192 teachers who worked in kindergartens or child care centers in Daegu and Gyeongbuk Province. Questionnaires, which require self-report by teachers, were used to investigate the emotional support from social network, ego-resiliency, and role conflict. The collected data were analyzed by Pearson's correlation, single and multiple regressions, using SPSS Win 15.0. The results are as follows. (1) Emotional support from social network and ego-resiliency was negatively associated with the role conflict of teachers in kindergartens and day care centers. (2) Emotional support from social network was positively associated with ego-resiliency. (3) Emotional support from social network partly exerted indirect effects on role conflict mediated by ego-resiliency. But direct effect of emotional support from social network on role conflict was more than the indirect effect. These results indicate that a higher level of emotional support from social network is more likely to lower role conflict of teachers.

• Hwankyungkyoyuk
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• v.12 no.1
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• pp.335-347
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• 1999

Restricted by time and space, formal environmental education has a limit in accommodating fast changing socal phenomena and quickly spreading environmental problems. Therefore, to carry out more efficiently the environmental education for middle and high school students, this study is intended to search for a way to establish a network of formal and nonformal environmental education. More than 80% of civil environmental organizations replied they agree to establish a network of environmental education. As for the establishment of a network, they preferred the establishment in which middle and high school, civil environmental organizations, government, the environment-related departments of the universities. They preferred ‘civil environmental organizations’ for the operator, ‘local municipal or provincial level for the scale, ‘direct personal relations’ for the interchange method. To establish a network, they replied that ‘funding’, ‘specialists in environmental education’, ‘staff to proceed educations’, ‘reform of law and systems’ are required. They also preferred ‘funding from government budget’ for a way to fund a network. We can draw the following conclusions from the survey, We need a training program for environmental education staff not to make those educational programs by civil environmental organizations temporary Also, more studies should be done to establish more organized network of environmental education and nonformal environmental education by civil environmental organizations. Environmental problem varies depending on the local characteristics, and thus environmental education should be carried out locally at the network center for environmental education. Besides, local self-governing bodies should support it administratively and financially.

• Proceedings of the KSR Conference
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• 2002.10a
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• pp.484-489
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• 2002

Whenever the accidents occur in the railway areas, their prompt recovery is very important. The individual way has been used to resolve these accidents by direct visiting the site and reporting to others who cares for these cases. As a result, we are planning to operate the MTS (Moving picture Transmission System) for a timely information's transmission to the related peoples in the central control center by transforming the picture information on the accident-site to the digital information. The proposed system is not a transmission system using exclusive lines, but utilizing the existing railway computer network. We construct a network server device so that a dispatcher can easily connect with the server through the railway intranet. In some railway environments such as disturbed field situations and geographical condition(in tunnels and bridges, etc) building up the wired network is difficult. Solving this problem, we reviewed the wireless network. Finally we proposed the mixed wireless network that is able to cover the wired network. We then installed and tested the wired network and wireless network respectively in wayside of a railway field. Through the testing, we identified many detailed matters for some network construction approaches to the control room and many field device-connecting schemes. This research will contribute to minimize the number of staff dispatched to a disturbed field, decrease the accident recovery time and improve the quality of service to the passenger.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.1
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• pp.90-97
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• 2004

DC motor requires a rotor speed sensor for accurate speed control. The speed sensors such as resolvers and encoders are used as speed detectors. but they increase cost and size of the motor and restrict the industrial drive applications. So in these days. many Papers have reported on the sensorless operation or DC motor(3)-(5). This paper Presents a new sensorless strategy using neural networks(6)-(8). Neural network structure has three layers which are input layer. hidden layer and output layer. The optimal neural network structure was tracked down by trial and error and it was found that 4-16-1 neural network has given suitable results for the instantaneous rotor speed. Also. learning method is very important in neural network. Supervised learning methods(8) are typically used to train the neural network for learning the input/output pattern presented. The back-propagation technique adjusts the neural network weights during training. The rotor speed is gained by weights and four inputs to the neural network. The experimental results were found satisfactory in both the independency on machine parameters and the insensitivity to the load condition.

• Journal of Ecology and Environment
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• v.48 no.3
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• pp.256-262
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• 2024

Background: Research investigating the relationship between latitude and network specialization plant-pollinator networks present conflicting results. While some studies indicate a positive link between latitude and network specialization, particularly in tropical regions, others suggest contradictory trends, with specialization declining towards lower latitudes. These studies underscore the intricate nature of ecological specialization in plant-pollinator networks and the need for further studies in this field to gain a more nuanced understanding of the underlying mechanisms driving these patterns. In this study, we explore the relationship between plant-pollinator network specialization and latitude using a global dataset comprising 93 plant-pollinator networks. Results: Our analysis revealed a significant relationship with latitude mostly in the Southern Hemisphere, particularly concerning metrics such as connectance and nestedness. However, notably, we found no association with H2, a metric immune to the size, shape, or sampling effects of the network and considered highly suitable for measuring network specialization in both Hemispheres. Conclusions: The absence of latitudinal trends in network specialization (H2) in both Hemispheres in this study imply that the mutual attraction between plants and pollinators remains relatively stable across various latitudes. Our comparison with prior research highlights the diversity of conclusions regarding how latitude influences plant-pollinator networks. While our results are consistent with certain studies, indicating no direct impact of latitude on network specialization, discrepancies persist.