• Journal of the Korea Computer Industry Society
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• v.4 no.10
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• pp.731-740
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• 2003

Since motion estimation remove the redundant data to employ the temporal correlations between adjacent frames in a video sequence, it plays an important role in digital video coding. And in the block matching algorithm, search patterns of different shapes or sizes and the distribution of motion vectors have a large impact on both the searching speed and the image quality. In this paper, we propose a new fast block matching algorithm using the small-cross search pattern and the block-based gradient descent search pattern. Our algorithm first finds the motion vectors that are close to the center of search window using the small-cross search pattern, and then quickly finds the other motion vectors that are not close to the center of search window using the block-based gradient descent search pattern. Through experiments, compared with the block-based gradient descent search algorithm(BBGDS), the proposed search algorithm improves as high as 26-40% in terms of average number of search point per motion vector estimation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.11a
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• pp.371-374
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• 2004

Induction motors are a critical component of many industrial processes and are frequently integrated in commercially available equipment. Safety, reliability, efficiency, and performance are some of the major concerns of induction motor applications. Preventive maintenance of induction motors has been a topic great interest to industry because of their wide range application of industry. Since the use of mechanical sensors, such as vibration probes, strain gauges, and accelerometers is often impractical, the motor current signature analysis (MACA) techniques have gained murk popularity as diagnostic tool. Fault tolerant control (FTC) strives to make the system stable and retain acceptable performance under the system faults. All present FTC method can be classified into two groups. The first group is based on fault detection and diagnostics (FDD). The second group is independent of FDD and includes methods such as integrity control, reliable stabilization and simultaneous stabilization. This paper presents the fundamental FDD-based FTC methods, which are capable of on-line detection and diagnose of the induction motors. Therefore, our group has developed the embedded distributed fault tolerant and fault diagnosis system for industrial motor. This paper presents its architecture. These mechanisms are based on two 32-bit DSPs and each TMS320F2407 DSP module is checking stator current, voltage, temperatures, vibration and speed of the motor. The DSPs share information from each sensor or DSP through DPRAM with hardware implemented semaphore. And it communicates the motor status through field bus (CAN, RS485). From the designed system, we get primitive sensors data for the case of normal condition and two abnormal conditions of 3 phase induction motor control system is implemented. This paper is the first step to drive multi-motors with serial communication which can satisfy the real time operation using CAN protocol.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.355-362
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• 2007

Diabetes mellitus can cause devastating complications, which often result in disability and death, and diabetic nephropathy is a leading cause of death in people with diabetes. In this study, we tried to predict the onset of diabetic nephropathy from an irregular and unbalanced diabetic dataset. We collected clinical data from 292 patients with type 2 diabetes and performed preprocessing to extract 184 features to resolve the irregularity of the dataset. We compared several feature selection methods, such as ReliefF and sensitivity analysis, to remove redundant features and improve the classification performance. We also compared learning methods with support vector machine, such as equal cost learning and cost-sensitive learning to tackle the unbalanced problem in the dataset. The best classifier with the 39 selected features gave 0.969 of the area under the curve by receiver operation characteristics analysis, which represents that our method can predict diabetic nephropathy with high generalization performance from an irregular and unbalanced dataset, and physicians can benefit from it for predicting diabetic nephropathy.

• The Journal of the Korea Contents Association
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• v.10 no.8
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• pp.451-460
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• 2010

The purpose of this paper is to present the effective operation method of cyber home learning system 2.0. Cyber home learning system 2.0 which plays an important role to produce and share data of internet users establishing user-centered internet environment is recently introduced as web 2.0 is beginning to appear. This research is based on the case of the operation on cyber home learning system, research literature of web 2.0 as well as expert consulting and performance test. After doing this research, cyber home learning system 2.0 can bring enormous educational effect when it has online education using web-based discussion tool and long distance consulting linking with off line school education. Redundant system configuration, the distributed processing also may be provided by the service was smooth. Moreover, it demands monitoring team consisting of student, parents and teacher in order to provide developmental service.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.628-640
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• 2004

The demand for next generation networks can be condensed into always-best-connected, ubiquitous, mobile, all-lP, and converged networks. IPv6 has been introduced for all-IP ubiquitous communications, and vehicles are coming to represent an important communication platform. In this paper. we propose various resource management schemes for in-vehicle mobile networks, which are adaptive to different hardware configurations. We focus on power and wireless bandwidth since they are critical resources for mobile communications. Based on the mobility characteristics of in-vehicle networks, we propose vehicle-aware power saving schemes. The main idea behind these power saving schemes is to adjust mobile router (MR) advertisement interval and binding lifetime. In addition, according to different wireless environments, we propose adaptive bandwidth management schemes using multihoming: best-connected MR selection based on location, and high-data-rate MR selection based on priority By mathematical analysis, it is shown that our schemes save power prominently for both the dormant nodes and active nodes. In addition, simulation results show that proposed multiple mobile router architecture outperforms previous simple redundant router architecture in preserving session and providing sufficient bandwidth.

• Spatial Information Research
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• v.8 no.1
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• pp.15-29
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• 2000

In the Recent rapidly changing technology environment the computerization of administration business which is driven or will be driven to give improved information services to people by local government or central government with a huge budget. The possibility of applying GIS application component to the computerization of administration business is investigated to prevent local government from investing redundant money and to reuse the existing investment at this point of time. Land civil service application component was developed at the $\ulcorner Development of Open GIS Component S/W \lrcorner$ project which was managed by Ministry of Information and Communication . GIS application component was based on Open GIS OLE/COM specification for development of standard interface and USD(Unified System Development ) for development method and UML (Unified Modeling Language) for system design and Visual C++ for component implementation. Implemented components were Process Control, Map, Print, Statistics component and were verified by using Visual Basic and Delhi. tis study shows that the development of component is very useful at the GIS application development for local governments. But the standard of business and data and system is the essential prerequisite to maximize business application.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.7
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• pp.653-660
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• 2013

This paper deals with the problem of unfairness among uplink TCP (Transmission Control Protocol) flows associated with frame aggregation employed in IEEE 802.11n WLANs (Wireless Local Area Networks). When multiple stations have uplink TCP flows and transmit TCP data packets to an AP (Access Point), the AP has to compete for channel access with stations for the transmission of TCP ACK (acknowledgement) packets to the stations. Due to this contention-based channel access, TCP ACKs tend to be accumulated in the AP's downlink buffer. We show that the frame aggregation in the MAC (Medium Access Control) layer increases TCP ACK losses in the AP and leads to the serious unfair operation of TCP congestion control. To resolve this problem, we propose the TAC (TCP ACK Compression) mechanism operating at the top of the AP's interface queue. By exploiting the properties of cumulative TCP ACK and frame aggregation, TAC serves only the representative TCP ACK without serving redundant TCP ACKs. Therefore, TAC reduces queue occupancy and prevents ACK losses due to buffer overflow, which significantly contributes to fairness among uplink TCP flows. Also, TAC enhances the channel efficiency by not transmitting unnecessary TCP ACKs. The simulation results show that TAC tightly assures fairness under various network conditions while increasing the aggregate throughput, compared to the existing schemes.

• The Journal of Korean Association of Computer Education
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• v.16 no.5
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• pp.39-47
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• 2013

In the case of a weak self-control youth, young students easily tend to fall into addiction by using the Internet as a sensation seeking and an alternative to escape the reality. Until now, internet addiction self-diagnosis techniques such as Internet addiction scale have been developed and used to solve this kind of internet addiction issue. However, traditional methods do not assess the correlation of addiction and the effects of the environment systematically because they are simply composed of redundant addiction scale criteria and questionnaire forms of the diagnostic methods. Thus, in this paper, we propose a new internet addiction self-diagnosis technique based on Formal Concept Analysis (FCA) and implement a self-diagnosis system in order to make a systematic internet addiction self-diagnosis system. In addition, we analyze the correlation of the measured data based on different perspectives such as home environment, family relationships, peer relationships, school life, and so on.

• Journal of Family Resource Management and Policy Review
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• v.17 no.3
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• pp.125-144
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• 2013

This aim in this study is to investigate the meaning of case management and management in general from the case manger's perspective, as well as case mangers' abilities and networks. We also propose a development direction for the establishment of a local integrated family-centered community management system. Regarding the collection of qualitative data, focus group interviews (FGIs) were conducted with 11 case managers from social welfare organizations in the city of C. The interviews consisted of open-ended questions in the following four categories: understanding of case management, case managers' abilities, case management environments, and local community networks. According to the interview analysis, a total of 16 subcategories in 9 categories and 4 domains have been identified. Due to the ambiguity regarding the concept of case management, case management was completely dependent upon individual case managers' abilities. In particular, family-centered case management was found to exist in several organizations in the same region. In terms of case management environments, the following problems have been observed: absence of related departments and staff, confusion regarding performance evaluation standards, limitations in sharing information among organizations, limitations in resource exploration and management, redundant support, and an uncomfortable relationship between the private and public sector. Horizontal exchange and cooperation among organizations are essential to establish and facilitate a local community network. After all, to establish a local family-centered community case management system, the roles of a Healthy Families Center and a Multi-cultural Family Support Center as parts of a family-centered transfer system should be fully emphasized in local society, and the performance of family-centered case management should be developed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.5A
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• pp.381-390
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• 2009

In this paper, we propose a seamless intra MR-BS handover scheme based on IEEE802.16j transparent. The proposed scheme estimates the outage probability of mobile stations at a base station, finds the optimum relay user, and provides low handover latency for seamless data transmission. The simulation results show that the proposed scheme outperforms the conventional handover schemes in terms of the handover latency by 65% of conventional scheme. Moreover, the proposed scheme exhibits lower packet error rate compared with the conventional handover scheme when a mobile station moves to outside of the cell coverage and reduce both outage probability and the number of handover about 50% from setting forgetting factor and redundant threshold.