• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.389-405
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• 2001

In these days, we have increasing demands on the real-time services, especially for the multimedia data transmission in both of wired and wireless environments and thus efficient and stable ways of transmitting realtime data are needs. Although RTP is widely used for internet-based realtime applications, it cannot avoid packet losses, due to the use of UDP stack and its underlying layers. In the case of mobile computing applications, the packet losses are more frequent and consecutive because of the limited bandwidth. In this paper, we first statistically analyze the characteristics of packet losses in the wired and wireless communications, based on Gilbert model, and a new packet recovery scheme for realtime data transmission is presented. To reflect the transmission characteristics of the present network environment, our scheme makes the sender to dynamically adjust the amount of redundant information, using the current packet loss characteristic parameters reported by the receiver. Additionally, we use relatively large and discontinuous offset values, which enables us to recover from both of the random and consecutive packet losses. Due to these characteristics, our scheme is suitable for the mobile computing environment where packet loss rates are relatively high and varies rapidly in a wide range. Since our scheme is based on the analytic model form statistics, it can also be used for other network environments. We have implemented the scheme with Mobile IP and RTP/RTCP protocols to experimentally verify its efficiency.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.93-99
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• 2008

In this paper, we propose new modulation schemes using the conventional CACB modulation with constant amplitude property. Also the proposed modulation schemes supports high transmission data rate by increasing the spectral efficiency. In order to obtain the high spectral efficiency, the $Q^2$PSK and CA-$Q^2$PSK are used. We explain the simplest combining modulation scheme of CACB and $Q^2$PSK (i.e., CACB-$Q^2$PSK). However, this modulation scheme cannot support the constant amplitude property. Hence the first CACB-CA-$Q^2$PSK (or CACB-CA-$Q^2$PSK I) modulation scheme is proposed for the constant amplitude property. In the modulation scheme, the redundant constant amplitude encoding (spectral efficiency decrease) is required. Therefore, the second CACB-CA-$Q^2$PSK (or CACB-CA-$Q^2$PSK II) modulation scheme is proposed retaining the constant amplitude and the spectral efficiency. Computer simulations show that the proposed CACB-CA-$Q^2$PSK II is the efficient modulation scheme.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.1
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• pp.18-29
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• 2008

NAND Flash memory has been growing popular storage device for the last years because of its low power consumption, fast access speed, shock resistance and light weight properties. However, it has the distinct characteristics such as erase-before-write architecture, asymmetric read/write/erase speed, and the limitation on the number of erasure per block. Due to these limitations, various Flash Translation Layers (FTLs) have been proposed to effectively use NAND flash memory. The systems that adopted the conventional FTL may result in severe performance degradation by the hot data which are frequently requested data for overwrite in the same logical address. In this paper, we propose a novel FTL algorithm called Adaptive Flash Translation Layer (AFTL) which uses sector mapping method for hot data and log-based block mapping method for cold data. Our system removes the redundant write operations and the erase operations by the separating hot data from cold data. Moreover, the read performance is enhanced according to sector translation that tends to use a few read operations. A series of experiments was organized to inspect the performance of the proposed method, and they show very impressive results.

• Archives of Plastic Surgery
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• v.36 no.3
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• pp.356-360
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• 2009

Purpose: Lipofibromatous Hamartoma(LFH) of nerve is a tumor - like lipomatous process principally involving the young persons. This is rare disease characterized by a soft slowly growing mass surrounding and infiltrating major nerves and their branches of the palm and digits. LFH of nerve usually affects the median nerve, with the most common sites of presentation being the distal forearm and hand in the wrist or palm. It may cause symptoms of compression neuropathy and is associated with macrodactyly. Recently, MRI plays a major role in confirming the diagnosis of LFH. Therefore, we present two cases of LFH in the hand with MRI features and surgical management. Methods: One is 6 - years - old female who presented with macrodactyly involving both the soft tissue and bony parts of the second, third and forth digits of her right hand. The other one is 16 - years - old man who presented involving the soft tissue of the second and third digits of his right hand, with pain and numbness, along with motor and sensory deficits in the median nerve distribution. To evaluation about LFH, we enforced preoperative MRI and physical examination. After confirming the diagnosis of LFH, we proposed decompression of all compromised peripheral nerve to help alleviate pain and paresthesia to reduce the likelihood of permanent motor and sensory sequelae. Results: A characteristic feature on MRI is the appearance of serpentiform nerve fascicle surrounded by fibro - fatty tissue within the expended nerve sheet. Distribution of fat between fascicles is asymmetric. Two cases were treated by limited debulking of the redundant tumor tissue and excision of epineurial fatty tissue. These cases were performed with relief of symptom. Conclusion: MRI not only confirms the diagnosis, it also provides a detailed assessment of nerve involvement preoperatively. Especially, on coronal images, the nerve has a spagetti - like appearance that is pathognomonic of LFH. Recommendations for early treatment include decompression of the carpal tunnel, debulking of the fibro - fatty sheath, microsurgical dissection of the neural elements and excision of involve nerve with or without grafting.

• Progress in Medical Physics
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• v.19 no.4
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• pp.247-255
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• 2008

A coded aperture camera has been developed to improve the signal-to-noise ratio (SNR) while keeping the spatial resolution of a pinhole gamma camera. The purpose of this study was to optimize a coded aperture camera and to evaluate its possibility for thyroid imaging by Monte Carlo simulation. A clinical gamma camera, a pinhole collimator with 1.0 mm hole diameter, and a $79{\times}79$ modified uniformly redundant array (MURA) mask were designed using GATE (Geant4 Application for Tomographic Emission). The penetration ratio, spatial resolution, integral uniformity and signal-to-noise ratio (SNR) were simulated and evaluated as a function of the mask thickness. The spatial resolution of the coded aperture camera was consistent with the various mask thickness, SNR showed a maximum value at 1.2 mm mask thickness and integral uniformity was improved by increasing mask thickness. Compare to the pinhole gamma camera, the coded aperture camera showed improved SNR by a factor of 30 while keeping almost the same spatial resolution. In this simulation study, the results indicated that high spatial resolution and ultra-high SNR of the thyroid imaging are feasible using a coded aperture camera.

• Information Systems Review
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• v.10 no.2
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• pp.291-308
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• 2008

This study is to review the main concepts of BSC(Balance Scorecard) and compare the BSCs applied in the private and the public sectors. This comparison suggests a few important aspects that must be attended when BSC is put to use in the public organization. First, the BSC used in the public sector must put the top priority to customer perspective over financial one. The primary mission of a public organization must be the "better service" for the people. Secondly, each of BSC's four main perspectives should be modified and re prioritized according to the goals and objectives of the public organization. Finally, CSFs(Critical Success Factors) and KPIs(Key Performance Indicators) must be integrated into the framework of BSC which also incorporates already existing performance management systems. This case study shows how the redundant and unrelated performance management systems(evaluation management, government task evaluation, job performance appraisal, and customer satisfaction evaluation) are merged into the BSC performance management system in the public organization.

• Science of Emotion and Sensibility
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• v.12 no.4
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• pp.433-442
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• 2009

People are tending to buy products through the Internet rather than purchasing them from the store. Some of the consumers give their feedback on line such as reviews, replies, comments, and blogs after they purchased the products. People are also likely to get some information through the Internet. Therefore, companies and public institutes have been facing this situation where they need to collect and analyze reviews or public opinions for them because many consumers are interested in other's opinions when they are about to make a purchase. However, most of the people's reviews on web site are too numerous, short and redundant. Under these circumstances, the emotion scanning system of text documents on the web is rising to the surface. Extracting writer's opinions or subjective ideas from text exists labeled words like GI(General Inquirer) and LKB(Lexical Knowledge base of near synonym difference) in English, however Korean language is not provided yet. In this paper, we labeled positive, negative, and neutral attribute at 4 POS(part of speech) which are noun, adjective, verb, and adverb in Korean dictionary. We extract construction patterns of emotional words and relationships among words in sentences from a large training set, and learned them. Based on this knowledge, comments and reviews regarding products are classified into two classes polarities with positive and negative using SO-PMI, which found the optimal condition from a combination of 4 POS. Lastly, in the design of the system, a flexible user interface is designed to add or edit the emotional words, the construction patterns related to emotions, and relationships among the words.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.5
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• pp.365-373
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• 2013

Tile caching technology is a commonly used method that optimizes the delivery of map imagery across the internet in modern WebGIS systems. However the poor performance of the map tile cache update is one of the major causes that hamper the wider use of this technique for datasets with frequent updates. In this paper, we introduce a new algorithm, namely, Partial Area Cache Update (PACU) that significantly minimizes redundant update of map tiles where the update frequency of source map data is very large. The performance of our algorithm is verified with the cadastral map data of Pyeongtaek of Gyeonggi Province, where approximately 3,100 changes occur in a day among the 331,594 parcels. The experiment results show that the performance of the PACU algorithm is 6.6 times faster than the ESRI ArcGIS SERVER$^{(r)}$. This algorithm significantly contributes in solving the frequent update problem and enable Web Map Tile Services for data that requires frequent update.

• Anxiety and mood
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• v.13 no.2
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• pp.74-85
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• 2017

Objective : A variety of approaches are needed to solve high suicide rates in Korean society. Although suicide prevention education has been provided for the public and suicide risk groups in Korea, a systematic discussion of simple, effective suicide prevention guidelines for the general public has yet to be made. Self-help guidelines for suicide prevention, which can help prevent suicide in at risk individuals, will be developed through expert questionnaires. Methods : In order to develop the draft guidelines, suicide prevention self-help phrases were gathered and compiled from homepages and publicity materials of domestic and international suicide prevention and related organizations. A panel of 16 suicide prevention experts conducted primary and secondary surveys using the Delphi method, which derives results from consensus among expert groups. The validity and appropriateness of the guidelines was analyzed using content validity ratios (CVR). Results : Of 33 candidate phrases selected for the suicide prevention guidelines, 9 showed high CVR after the secondary Delphi round. The highest level of support with total agreement was given to 'Do not be alone, stay with someone'. However, more than half of the panelists evaluated 14/27 of the primary Delphi round and 12/26 of the secondary Delphi round phrases as invalid. The researchers completed 10 self-help guidelines for suicide prevention, after eliminating 1 redundant phrase and including 2 additional phrases that showed relatively high CVR. Conclusion : We have developed 10 self-help guidelines for suicide prevention through the consensus of experts. Further studies on the effects of the guidleines relative to suicide rates are needed after widespread dissemination.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.5
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• pp.1126-1132
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• 2009

We carried out this study to reduce the gaps between medical institutes and between medical personnels and help to improve medical service quality, by classifying diagnoses and related intervention through the development of standard nursing intervention and by computerizing protocols. We considered two processes: one is the development process of home nursing standard intervention, and the other is the process of computerizing its related protocols. For the former, research covered analysis of home health care practices, development of client assessment protocol, of patients diagnosis protocols, and of patients intervention protocol. For the latter, strategies for home health care information systems should be set up and it constituted four research contents of analysis, design, management and evaluation of the systems. We also trained and educated home nurses who work at home health service center, by making them use the manual of home health care information systems at a certain city of P. In this study, therefore, we developed elements of standard home health care mediation so that they could be included in the forms of home health information note, home health progress note, and home health progress summary, home health discharge summary. Because standard home health care intervention has been developed, it became easier to exchange information between different home heath service center offices, can prevent from missing or redundant information, and contribute to standardization of hospital terminologies when EMR and HMR are developed.