• Ocean Systems Engineering
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• v.2 no.3
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• pp.217-228
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• 2012

As the size of container ships continues to increase, not many existing harbors can host the super-container ship due to its increased draft and the corresponding dredging requires huge budget. In addition, the minimization of waiting and loading/offloading time is the most important factor in harbor competitiveness. In this regard, mobile-harbor concept has been developed in Korea to achieve much improved harbor capacity and efficiency. In developing the concept, one of the most important elements is the operability of crane between two or more floating bodies in side-by-side arrangement. The container ship is to be stationed through a hawser connection to an outside-harbor fixed-pile station with the depth allowing its large draft. The mobile harbors with smart cranes are berthed to the sides of its hull for loading/offloading containers and transportation. For successful operation, the relative motions between the two or more floating bodies with hawser/fender connections have to be within allowable range. Therefore, the reliable prediction of the relative motions of the multiple floating bodies with realistic mooring system is essential to find the best hull particulars, hawser/mooring/fender arrangement, and crane/docking-station design. Time-domain multi-hull-mooring coupled dynamic analysis program is used to assess the hydrodynamic interactions among the multiple floating bodies and the global performance of the system. Both collinear and non-collinear wind-wave-current environments are applied to the system. It is found that the non-collinear case can equally be functional in dynamics view compared to the collinear case but undesirable phenomena associated with vessel responses and hawser tensions can also happen at certain conditions, so more care needs to be taken.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.3
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• pp.47-59
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• 2007

IPv4 NAT, which often used in households or under SOHO environments, is one of the factors that delays IPv6 propagation. As IPv4 NAT does not operate properly under the transition mechanism like ISATAP or 6to4 that acts as IPv6-in-IPv4 tunneling type, Microsoft proposed Teredo in order to resolve this issue. However, tunneling transition mechanism like Teredo has a security problem. That is, being tunneled packets have dual IP headers; general firewall systems apply the filtering rules only to the outer header but not inner header when these packets pass the firewall. Furthermore, attacks using unregistered server and relay can take place in Teredo. To resolve these problems, we propose a new packet filtering mechanism exclusively for Teredo. The proposed packet filtering mechanism was designed and implemented by using Linux Netfilter and ip6tables. Through functional and experimental performance tests, this packet filtering system was found operating properly and solving the Teredo packet filtering problems without serious performance degradation.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2002.11a
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• pp.137-142
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• 2002

The purpose of this study was to examine the features that make residents feel “at home” in ALFs in Southwest Virginia and to suggest further policy and design guidelines for better Quality of ALFs as a “home.” For this purpose, residents' needs, experiences, and opinions of the physical environment, the social environment, and the organizational environments such as policies and programs of ALFs were identified. As a multi-case study, five ALFs in Southwest Virginia were studied using constant comparative methos of data analysis. In addition to face-to-face interviews with 25 residents and five administrators of five ALFs, observations were conducted with personal journal. Overall, the five sites selected presented homelike features showing the philosophy of assisted living which combines housing and services. Each facility was designed to be a single-family house or multi-family dwelling in outside appearance. As a whole, residents felt isolation and loneliness and they did not have active interaction with other residents because of diverse background among the residents. However, all of them had close relationships with the staff. The staff's attitude and behavior seemed to influence greatly the residents' feeling “at home.” Despite the provision of diverse activities by the facilities, many residents did not participate in the programs. Most of the residents agreed that the rule and regulations were fair. In spite of high satisfaction with the facility, many people did not think of their current dwelling as a real ‘home.’ As the biggest difference between living in their own homes and living in the ALF, people pointed out a lack of independence, freedom, and autonomy. Residents of ALFs may have reordered their priorities in their current life situation so that safety, security, and care were more important to them than feeling “at home.” Among the three factors --physical, social, and organizational-- that affect the residents' perception of ALFs as a “home, ” many emphasized the importance of social factors such as relationships with the staff and residents, and social support from their family or friends.

• Korean Journal of Health Education and Promotion
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• v.29 no.4
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• pp.15-28
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• 2012

Objective: This paper aims to describe health promotion (HP) research according to HP activities, strategies, target population, and settings, and to explore challenges for HP to reflect principles and values. Methods: A content analysis was employed for all research reports funded by the Korea Health Promotion Foundation from 2005 to 2011. Content analysis was conducted according to the HP activities and strategies as mentioned in the Ottawa Charter, and by target population and setting. Challenges for HP research were explored by priority actions suggested by the International Union for Health Promotion and Education. Results: The total number of research was 384. The most popular topic was on HP actions for reorienting health services, followed by developing personal skills, creating supportive environments, building healthy public policy, and strengthening community actions. Research focusing on enabling strategies was most dominant among the HP strategies, while both advocating and mediating strategies were unlikely to be studied. An even distribution was found across target populations. The most popular setting was communities, followed by workplaces and schools. Conclusion: HP research tends to be anchored on bio-medical, individualized, and behavioral perspectives. A discussion was made to overcome this tendency by employing HP in social sciences theory and methods.

• Journal of the Korea Convergence Society
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• v.11 no.3
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• pp.67-75
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• 2020

The 'level of difficulty' is one of the major factors for learners when selecting learning contents. However, the criteria for the difficulty level is mostly defined by the contents providers. This approach does not support the personalized education which should consider the abilities and environments of various learners. In this research, the knowledge of the learners and contents were formalized and generalized to resolve the issue, and object models, including a metric for personalized difficulty level, were designed in order to be applied for experiments. And then, based on 100 contents for music education and 20 learners, we performed simulations with an implemented tool to validate our approach. The experimental results showed that our method can calculate the personalized difficulty levels considering the similarities between the knowledges from the learning state and the contents. Our approach can be effectively applied to the on-line learning management system which contains easy access to the learning state and contents data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.226-234
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• 2005

Context-Aware is the most important facts to reason a personalized and optimized service and to provide it to user. In the previous researches, user and surrounding environment were main facts of Context-Aware and middleware or center server has been proposed to support Context-Aware. In the daily space(for example, home, office, Car, etc), interactions between user and service can be a important facts of Context-Aware. In this paper, Context Autogenesis service model is introduced, simplified the Context-Aware process and designed the middleware which performs decentralize management for Context-Aware information of user's portable devices, so that problems occurred during the management and operation of existing Context-Aware system can be minimized and supporting user anonymity

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.8B
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• pp.716-729
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• 2006

The information systems in the most enterprise environments are distributed locally and are comprised with various heterogeneous data sources, so that it is difficult to obtain necessary and integrated information for supporting user decision. For solving 'this problems efficiently, it provides uniform interface to users and constructed database systems between heterogeneous systems make a consistence each independence and need to provide transparency like one interface. This paper presents XMDR that consists of category, standard ontology, location ontology and knowledge base. Standard ontology solves heterogeneous problem about naming, attributes, relations in data expression. Location ontology is a mediator that connects each legacy systems. Knowledge base defines the relation for sharing glossary. Adaptive retrieve proposes integrated retrieve system through reflecting site weight by location ontology, information sharing of various forms of knowledge base and integration and propose conceptual domain model about how to share unstructured knowledge.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1461-1472
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• 2000

Recently, the mobile users seem to be rapidly increasing and then the capacity limit will be reached at close hand. In these situations, to provide them with good quality of service in the coming future, newly planned cell design is needed. In the next generation mobile communication systems, namely IMT-2000, good quality services will be possible only by designing the cell structure hierarchically with the help of appropriate cell planning. In the research process, the standardization reports on the future mobile cellular IMT-2000 system (3GPP) are investigated and the parameters, that are essential to cell planning, are also researched. Modeling of IMT-2000 radio link and the numerical analysis on that make it possible to calculate the forward/reverse link budget, system capacity call blocking probability Erlang capacity and cell coverage. In planning the cell of IMT-2000 system, various parameters are considered, such as hierarchical cell structure, number of users, data service forms and propagation area environments. From the results, efficient cell planning methods are proposed. Through this thesis efficient cell planning and maximum capacity will be achieved in the beginning of commercial IMT-2000 service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.983-990
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• 2008

In communication systems, initial acquisition is required for the reliable transmission performance, and the analysis of the acquisition performance over various communication environments including different signal-to-noise ratios plays an important role in communication system design. Usage of differential correlation methods in initial synchronization procedure is desired when frequency offsets exist, and additional performance improvement can be achieved through proper modifications of conventional correlation schemes. In this paper, we derive the error probability of the initial acquisition and express it in terms of the Marcum Q-function, via statistical modeling of the differential correlator output. The result is generalized to the error probabilities of the extended differential correlation methods using the complex- and magnitude-sum of the correlator outputs. The derived probabilities can be applied for the acquisition performance verification of various communication systems including the DVB-S2 standard.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.7
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• pp.572-580
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• 2013

IEEE 802.15.4e is a prospective standard for low latency control application in industries. This paper proposes a framework to evaluate the closed loop IEEE 802.15.4e based WNCS performance. The framework consists of two models: closed loop control system model and network model. The network model focuses on the PHY parameters of wireless link and takes the channel parameters into consideration. The PHY model combining with MAC model gives the control system model the probability of packet loss in a super-frame. In addition, redundancy mechanism is considered in IEEE 802.15.4e to reduce to data frame loss probability. The simulation is implemented in Matlab, PHY model takes the channel parameters from empirical results. Hence our evaluation gives insight into behavior of WNCS in different environments and it provides us a tool to design wireless network to achieve a good performance for control system.