• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.192-209
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• 2011

This study looked into coping strategies of local terrestrial broadcasting companies in the media market, since the introduction of comprehensive programming channels was confirmed. Local terrestrial broadcasting companies vulnerable to market competitiveness are driven more out to the difficulty of survival in a limited advertising market with the advent of comprehensive programming channel. and Local terrestrial broadcasting receive discriminative application than comprehensive programming channel. They have reverse discrimination in must-carry, broadcasting area, programming regulation, advertisement regulation, broadcasting development fund. Hence, Local terrestrial broadcasting needs diverse countermeasures at difficult media circumstances. Above all, Competitive content reinforcement is desperately needed. That's why content distribution structure needs diversification. And, It is necessary for local terrestrial broadcasting companies to diversify the content distribution system. As a way to expand distribution structure of local broadcasting, the introduction of local programming regulations for total amount will be highlighted in the nationwide network program. The mandatory policy that programs produced by local terrestrial broadcasting companies will be broadcast regularly in prime time through a nationwide network is an example. In addition to developing high content independently, 2nd Multiple channels of distribution is needed. It has to be supplied to various platforms including local broadcasting, SO and etc. In addition, it is necessary to activate regional co-production program between local terrestrial broadcasting companies and regions. Time rate between central stations and local terrestrial broadcasting companies must be distributed practically. And also, local terrestrial broadcasting companies in addition to ad revenue model to themselves and their own businesses by expanding the sponsorship to strengthen the competitiveness will have to nurture self-sustaining. Moreover they must have enlarge economy of scale through widen of broadcasting area.

• The Journal of Korean Association of Computer Education
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• v.11 no.4
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• pp.71-83
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• 2008

The recent advances of the information technology have motivated lots of research efforts to develop new computer-aided teaching and learning methodologies on various computer science topics, such as data structures, operating system, computer networks, and computer architecture. However, there have been only few studies to educate the database subject although it is one of the most important topics in the computer science. Specifically, among the various issues in the database subject, a learner often suffers to understand the mechanism of the concurrency control and recovery of database transaction in the database because it highly interacts with other functions in the database. Obviously, an intelligent visualization tool can help a learner to understand the process of the concurrency control and the recovery of database transaction. The purpose of this study is to develop an efficient visualization tool which can help users understand the two phase locking protocol (2PLP)-based concurrency control. Specifically, this visualization tool is designed to encourage a users' participation and raise their interest by visualizing the process of transactions and allowing users to specify and manipulate their own transactions.

• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.73-82
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• 2009

The peers in the Chord method send messages periodically to keep the routing table updated. In a mobile P2P network, the peers in the Chord method should send messages more frequently to keep the routing table updated and reduce the failure of a request. However this results in increasing the overall network traffic. In our previous method, we proposed a method to reduce the update load of the routing table in the existing Chord by updating it in a reactive way, but there were disadvantages to generate more traffic if the number of requests per second increases and to have more delay in the request processing time than the existing Chord. In this paper, we propose an improved method of reactive routing table update to reduce the request processing time. In the proposed method, when a data request comes, the routing table is updated only if its information is not recent while it is always updated in the previous method. We perform experiments using Chord simulator (I3) made by UC Berkely. The experimental results show the performance improvement of the proposed method compared to the existing method.

• Journal of the Korean Society for Library and Information Science
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• v.55 no.3
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• pp.57-77
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• 2021

The identity of public libraries in Japan is a social education institution under the 「Social Education Act」 and the 「Library Act」. For these identities, the local government's board of education has operated and managed public libraries, and some have managed by the Management Outsourcing System to public organizations. Then, in 2003, the 「Local Autonomy Act」 was revised to introduce the Designated Manager System in form of administrative disposition, and expanded the scope of application to private institutions and organizations. As of the end of 2018, 18.0% of public libraries introduced the DMS, but the pros and cons surrounding it are sharply opposed. This study outlined the overall status of the DMS and the introduction of public libraries, and critically reviewed major issues. As a result, As a result, there was much controversy over the expected cost reduction, service improvement, employee professionalism, business continuity, and cooperation network establishment when DMS was introduced. The reasons were due to downsizing-based personnel management, contract-oriented employment, short periods of designation, lack of multiple competitive markets, and declining service capabilities of irregular workers. The public library is a knowledge and cultural infrastructure that enhances human values and social dignity based on faithful collection and active service, and is a local public goods that emphasizes non-exclusion and non-competitiveness. Given the increasing number of cases in which public libraries are recently contracting out to cultural foundations in Korea, DMS is not a fire across the river. We need to be wary of the possibility that Japan's unbearable institutional lightness will be applied to public libraries in Korea.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.6
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• pp.151-158
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• 2010

In line with the requirement of appropriate protocol support for such mission-critical wireless sensor network (WSN) applications as patient monitoring, we investigate the framework for designing medium access control (MAC) schemes. The data traffic in medical systems comes with inherent traffic heterogeneity as well as strict requirement of reliability according to the varied extents of devise-wise criticality in separate cases. This implies that the quality-of-Service (QoS) issues are very distinctly delicate requiring specialized consideration. Besides, there are features in such systems that can be exploited during the design of a MAC scheme. In a monitoring or routine surveillance application, there are degrees of regularity or predictability in traffic as coordinated from a node of central control. The coordinator thus takes on the role of marshaling the resources in a neighborhood of nodes deployed mostly for upstream traffic; in a collision-free scheme, it schedules the time slots for each superframe based on the QoS specifications. In this preliminary study, we identify the key artifacts of such a MAC scheme. We also present basic performance issues like the impact of superframe length on delay incurred, energy efficiency achieved in the network operation as obtained in a typical simulation setup based on this framework.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.123-132
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• 2002

The purpose of this study is to predict the shear behavior of the weathered mudstone soil using dynamic neural network which mimics the biological system of human brain. SNN and RNN, which are kinds of the dynamic neural network realizing continuously a pattern recognition as time goes by, are used to predict a nonlinear behavior of soil. After analysis, parameters which have an effect on learning and predicting of neural network, the teaming rate, momentum constant and the optimum neural network model are decided to be 0.5, 0.7, 8$\times$18$\times$2 in SU model and 0.3, 0.9, 8$\times$24$\times$2 in R model. The results of appling both networks showed that both networks predicted the shear behavior of soil in normally consolidated state well, but RNN model which is effective fir input data of irregular patterns predicted more efficiently than SNN model in case of the prediction in overconsolidated state.

• Journal of the Korean earth science society
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• v.37 no.2
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• pp.117-131
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• 2016

The purpose of this study was to compare of freshmen's cognitive frames about the 'Crisis of the Earth' upon taking the Earth science I course in high school to confirm if they reflect the goal of the curriculum reasonably. Data were collected from 67 freshmen who graduated from high school. All participants were asked to express about the 'Crisis of the Earth' in painting with explanation, then we picked meaningful units from paintings. We analyzed the words and frames presented in the paintings using the Semantic Network Analysis. Result are as follows. First, when both groups' (one that took the course vs. the other that did not take it) built their cognitive frames for the 'crisis of the Earth', they reasonably connected areas that are composed of the global environment and they understood that their relation was constantly changing by interacting each other. Second, when configuring a cognitive frame about the 'crisis of the Earth', both groups reflected the characteristics of interrelationship with human activities. In particular, the group that took the course of Earth Science I fully reflected the goal of the curriculum. It is suggested that students recognize the 'crisis of the Earth' not only from a cosmic perspective bot also from the Earth's interior since most of students have strongly connected it to the phenomenon of the Earth's interior rather than the Earth's outward symptoms. In addition, it is recommended that the Earth science curriculum put more emphasis on understanding the importance of problem-solving of the Earth's crisis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.291-298
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• 2021

In this study, the future of countermobility capability is presented by analyzing the status of the countermobility obstacles focusing on the history of landmines and munitions. The conventional landmine was forbidden globally by the CCW and Ottawa Treaty because it caused civilian damage after the war. Because the inhumanity of those mines had been acknowledged, shatterable mines with a self-destruct (SD) function and M93 "HORNET" anti-tank munition with enhanced sensors have been fielded. In 2016, the Obama administration announced a policy that banned all antipersonnel landmines, leaving a considerable gap in the countermobility capability. To deal with these problems, the developments of "SAVO" and the SLEP program of Volcano mines were conducted. In the sense of a long-term approach, the countermobility obstacles, including mines, were chosen as fundamental forces for Multi-Domain Operations and were improved to Terrain Shaping Obstacles (TSO). TSO has improved sensors and mobility kill capabilities and features an enhanced remote control over each munition on the battlefield through a network established with satellite communication. The combined arms countermobility might be fully capable until 2050 if the TSO program can be completed successfully.

• Journal of KIISE:Information Networking
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• v.32 no.3
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• pp.415-426
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• 2005

Wireless internet, which becomes a hot social issue, has limitations due to the following characteristics, as different from wired internet. It has low bandwidth, frequent disconnection, low computing power, and small screen in user terminal. Also, it has technical issues to Improve in terms of user mobility, network protocol, security, and etc. Wireless internet server should be scalable to handle a large scale traffic due to rapidly growing users. In this paper, wireless internet proxy server clusters are used for the wireless Internet because their caching, distillation, and clustering functions are helpful to overcome the above limitations and needs. TranSend was proposed as a clustering based wireless internet proxy server but it has disadvantages; 1) its scalability is difficult to achieve because there is no systematic way to do it and 2) its structure is complex because of the inefficient communication structure among modules. In our former research, we proposed the All-in-one structure which can be scalable in a systematic way but it also has disadvantages; 1) data sharing among cache servers is not allowed and 2) its communication structure among modules is complex. In this paper, we proposed its improved scheme which has an efficient communication structure among modules and allows data to be shared among cache servers. We performed experiments using 16 PCs and experimental results show 54.86$\%$ and 4.70$\%$ performance improvement of the proposed system compared to TranSend and All-in-one system respectively Due to data sharing amount cache servers, the proposed scheme has an advantage of keeping a fixed size of the total cache memory regardless of cache server numbers. On the contrary, in All-in-one, the total cache memory size increases proportional to the number of cache servers since each cache server should keep all cache data, respectively.

• Journal of KIISE:Information Networking
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• v.35 no.5
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• pp.384-394
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• 2008

A wireless router is a device which allows several wireless clients to share an internet line using NAT (Network Address Translation). In a school or a small office environment where many clients use multiple wireless routers, a client may select anyone of wireless routers so that most clients can be clustered to a small set of the wireless routers. In such a case, there exists load unbalancing problem between clients and wireless routers. One of its result is that clients using the busiest router get poor service. The other is that the resource utilization of the whole wireless routers becomes very low. In order to resolve the problems, we propose a load sharing scheme to maximize network bandwidth utilization based on multiple SSID. In a time internal, the proposed scheme keeps to show the available bandwidth information of all the possible wireless routers to clients through multiple SSID. A new client can select the most available band with router. This scheme allows to achieve a good load balancing between clients and routers in terms of bandwidth utilization. We implemented the proposed scheme with ASUS WL 500G wireless router and performed experiments. Experimental results show the bandwidth utilization improvement compared to the existing method.