• Journal of the Korea Society of Computer and Information
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• v.14 no.9
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• pp.11-19
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• 2009

A RAM-based Neural Net(RBNN) which has multi-discriminators is more effective than RBNN with a discriminator. Experience Sensitive Cumulative Neural Network and 3-D Neuro System(3DNS) that accumulate the features point improved the performance of BNN, which were enabled to train additional and repeated patterns and extract a generalized pattern. In recognition process of Neural Net with multi-discriminator, the selection of class was decided by the value of MRD which calculates the accumulated sum of each class. But they had a saturation problem of its memory cells caused by learning volume increment. Therefore, the decision of MRD has a low performance because recognition rate is decreased by saturation. In this paper, we propose the method which improve the MRD ability. The method consists of the optimum MRD and the matching ratio prototype to generalized image, the cumulative filter ratio, the gap of prototype response MRD. We experimented the performance using NIST database of NIST without preprocessor, and compared this model with 3DNS. The proposed MRD method has more performance of recognition rate and more stable system for distortion of input pattern than 3DNS.

• Journal of the Korean Academic Society of Industrial Cluster
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• v.1 no.1
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• pp.67-86
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• 2007

Wonju Medical Equipment Industry, despite of its short history, poor sales and weak manpower and so on, have shown remarkable outcomes in a relatively short period. At the end of 2007, totally 79 enterprises (only 4.6% of whole enterprises in Korea) made 10% of the nationwide production and 15% of the nationwide exports with an annual average growth rate of 66.7%, contributing domestic medical equipment industry tremendously. In addition, many leading medical equipment enterprises in various fields already moved or plan to move to Wonju, accelerating Wonju Medical Equipment Cluster. Wonju Medical Equipment Industry Cluster now enters into the growth stage, getting out of the initial business setup stage. Especially, the nomination of Wonju cluster project from the government accelerates networking (e.g. the development of the universal parts, the establishment of the mutual collaboration model among enterprises, and the mutual marketing), making a rapid growth in Wonju Medical Equipment Industry. Wonju Medical Equipment Industry Cluster revealed positive outcomes despite of the weakness in investment size and infra-structure comparing with the other medical industry cluster in the advanced country, while many domestic enterprises pursued their own growth models and thus failed to promote the international competitive power. Wonju Medical Equipment Industry has been developed rapidly. However, there are many challenging problems to support enterprises: small R&D investment and thus weak technology power, difficulties in recruiting R&D engineers, and poor marketing capabilities, financial infrastructure & policies, and network architecture. In order to develop a world-competitive medical equipment industry cluster at Wonju, the complement of infrastructures, the technology innovation, the mutual marketing, and the network expansion to support enterprises are further required. Wonju' s experiences in developing medical equipment industry so far suggest that our own flexible cluster model considering the industry structure and maturity for different regions should be developed, and specific action plans from the local and central governments based on their systematic strategies for industry development should be implemented in order to build world-competitive industry clusters in Korea.

• Tunnel and Underground Space
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• v.13 no.1
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• pp.52-63
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• 2003

Discontinuities such as faults, fractures and joints in rock mass play the dominant role in the mechanical and hydraulic properties of the rock mass. The key factors that influence on the flow of groundwater are hydraulic and geometric characteristics of discontinuities and their connectivity. In this study, a program that analyzes groundwater flow in the 3D discontinuity network was developed on the assumption that the discontinuity characteristics such as density, trace length, orientation and aperture have particular distribution functions. This program generates discontinuities in a three-dimensional space and analyzes their connectivity and groundwater flow. Due to the limited computing capacity In this study, REV was not exactly determined, but it was inferred to be greater than 25$\times$25$\times$25 ㎥. By calculating the extent of aperture that influences on the groundwater flow, it was found that the discontinuities with the aperture smaller than 30% of the mean aperture had little influence on the groundwater flow. In addition, there was little difference in the equivalent hydraulic conductivity for the the two cases when considering and not considering the boundary effect. It was because the groundwater flow was mostly influenced by the discontinuities with large aperture. Among the parameters considered in this study, the length, aperture, and orientation of discontinuities had the greatest influence on the equivalent hydraulic conductivity of rock mass in their order. In case of existence of a fault in rock mass, elements of the equivalent hydraulic conductivity tensor parallel to the fault fairly increased in their magnitude but those perpendicular to the fault were increased in a very small amount at the first stage and then converged.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.3
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• pp.75-88
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• 2009

This paper presents a video quality assessment method based on quality degradation factors of real-time multimedia streaming services. The video quality degradation is caused by video source compression and network states. In this paper, we propose a blocky metric on an image domain to measure quality degradation by video compression. In this paper, the proposed boundary strength index for the blocky metric is defined by ratio of the variation of two pixel values adjacent to $8{\times}8$ block boundary and the average variation at several pixels adjacent to the two boundary pixels. On the other hand, unnatural image movement caused by network performance deterioration such as jitter and delay factors can be observed. In this paper, a temporal-Jerkiness measurement method is proposed by computing statistics of luminance differences between consecutive frames and play-time intervals between frames. The proposed final Perceptual Video Quality Metric (PVQM) is proposed by consolidating both blocking strength and temporal-jerkiness. To evaluate performance of the proposed algorithm, the accuracy of the proposed algorithm is compared with Difference of Mean Opinion Score (DMOS) based on human visual system.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.153-163
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• 2011

Smartphone is a mobile device which can perform better than feature phone. Recently, growth in demand for advanced mobile devices boasting powerful performance, market share of smartphone is increasing rapidly in mobile device market, for example, iphone and android phone. Smartphone can provide many functionalities, e-mail, scheduler, word-processing, 3D-game, and etc, based on its powerful performance. Thus, various secret information is integrated in smartphone. To provide service, sometimes, smartphone transmits informations to outside via wireless network. Because smartphone is a mobile device, user can lose his/her smartphone, easily, and losing smartphone can cause serious security threats, because of integrated information in smartphone. Also data which is transmitted in wireless network can be protected for privacy. Thus, in present, it is very important to keep secure smartphone. In this paper, we analyze threats and vulnerabilities of smartphone based on its environments and describe countermeasures against threats and vulnerabilities.

• Journal of Digital Convergence
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• v.15 no.9
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• pp.397-406
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• 2017

This study was conducted to identify moderating effects of interpersonal relation and social support on the relationship between depression and health promoting behaviors in the elderly. The participants were 286 elderly using two elderly welfare centers and one cultural center in D city. Data were collected from October 12th to 20th December, 2016, and were analyzed by t-test, ANOVA, multiple regression using SPSS 20.0. The result were as follows; The result were as follows; 1) Mean score of variables was Depression: 20.47, interpersonal relationship: 21.27 points, social support: 20.92 points, and health promotion behaviors: 111.69. 2) Depression had negative relationship with interpersonal relationship(r=-.283, p<.000), social network (r=-.391, p<.000), health promotion behaviors(r=-.611, p<.000), and interpersonal relationship had positive relationship with social support(r=.353, p<.000) and health promotion behaviors(r=.372, p<.000) significantly. 3) Social support had a moderating effect in the relationship between depression and health promoting behaviors(${\beta}=.448$, p=.011), while interpersonal relationship did not show moderation effect(${\beta}=.380$, p=.135). Based on these results, health program for elderly including social support is recommended to promote health behavior of the elderly in the community.

• KIISE Transactions on Computing Practices
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• v.22 no.8
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• pp.375-380
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• 2016

The proliferation of online social networking services (OSNSs) and smartphones has enabled people to easily make friends with a large number of users in the online communities, and interact with each other. This leads to an increase in the usage rate of OSNSs. However, individuals who have immersed into their digital lives, prioritizing the virtual world against the real one, become more and more isolated in the physical world. Thus, their socialization processes that are undertaken only through lots of face-to-face interactions and trial-and-errors are apt to be neglected via 'Add Friend' kind of functions in OSNSs. In this paper, we present a friend recommendation system based on the on/off-line contextual information for the OSNS users to have more serendipitous offline interactions. In order to accomplish this, we modeled both offline information (i.e., place visit history) collected from a user's smartphone on a 3D tensor, and online social data (i.e., friend relationships) from Facebook on a matrix. We then recommended like-minded people and encouraged their offline interactions. We evaluated the users' satisfaction based on a real-world dataset collected from 43 users (12 on-campus users and 31 users randomly selected from Facebook friends of on-campus users).

• Applied Chemistry for Engineering
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• v.35 no.4
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• pp.309-315
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• 2024

Silicon and carbon composite (SiC) is considered one of the most promising anode materials for the commercialization of Si-based anodes, as it could simultaneously satisfy the high theoretical capacity of Si and the high electronic conductivity of carbon. However, SiC active material undergoes repeated volumetric changes during charge/discharge processes, leading to continuous electrolyte decomposition and capacity fading, which is still considered an issue that needs to be addressed. To solve this issue, we suggest a 4,4'-Methylenebis(cyclohexyl isocyanate) (H₁₂MDI)-based waterborne polyurethane binder (HPUD), which forms a 3D network structure through thermal cross-linking reaction. The cross-linked HPUD (denoted as CHPU) was prepared using an epoxy ring-opening reaction of the cross-linker, triglycidyl isocyanurate (TGIC), via simple thermal treatment during the SiC anode drying process. The SiC anode with the CHPU binder, which exhibited superior mechanical and adhesion properties, not only demonstrated excellent rate and cycling performance but also alleviated the volume expansion of the SiC anode. This work implies that eco-friendly binders with cross-linked structures could be utilized for various Si-based anodes.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.119-124
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• 2010

디지털 제작, 압축 기술의 발전, 유무선 인터넷 보급 확산, 다양한 전송 및 서비스 플랫폼의 등장, 전송 기술의 광대역화, 단말 기술의 발전, 라이프스타일 변화와 킬러 서비스 등장으로 미디어 시장은 급속도로 발전하고 있다. 지상파 방송은 아날로그에서 디지털로 전환하고 있으며, 고화질, 다채널, 모바일, 3D 서비스를 제공하거나 제공할 예정에 있다. 현재 디지털 TV는 아날로그 TV와 동시 방송 형태로 제공되고 있지만 2012년말 디지털 TV로 완전한 전환을 앞두고 있으며, 모바일 TV인 DMB는 2005년말 본방송을 시작하여 전국 서비스를 제공하고 방송 커버리지를 확장하고 있다. FM과 AM의 디지털화를 위한 디지털 오디오 방송도 방식 선정을 위한 절차가 진행 중이다. 전파는 송신소에서 단말까지 전송되는 도중 신호레벨 감쇠, 페이딩, 왜곡, 잡음 유입 등을 겪게 된다. 양질의 지상파 방송을 제공하기 위해서는 전파가 수신 가능한 상태 이상의 양호한 상태로 시청자에게 전달되어야 한다. 이를 위해 방송사는 방송 수신 품질을 측정하고 수신이 불량한 지역에 대해서는 송신기 설치, 송신 출력 증강, 중계기 설치 등을 통해 양질의 서비스 제공이 가능한 방송 서비스 영역을 확대한다. 다양한 지상파 방송 매체에서 수신 품질 평가를 위해 가장 많이 측정하는 항목은 전계강도이다. 대부분의 경우 어떤 지역의 전계강도가 해당 매체가 요구하는 기준 레벨 이상이면 해당 지역을 양호 지역으로 평가한다. 본 논문에서는 다양한 지상파 방송 매체에 대한 전계강도를 측정하고 이를 분석할 수 있는 시스템을 제안하고자 한다. 제안 시스템을 이용하면 자동화된 절차에 의해 최단 시간에 다양한 지역에 대한 방송 수신 품질을 측정하고, 그 결과를 분석하여 방송 서비스 영역에 대한 평가를 내릴 수 있으며, 측정결과를 DB로 관리하여 동일 채널에 대한 이전 측정결과와 비교 분석, 다른 채널과 전계강도 비교 분석을 통해 특정 송신기 출력이 감소되거나 특정 안테나 출력에 문제가 발생한 경우에도 이를 쉽게 감지하여 최적의 방송망 구축 및 관리가 가능하다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.4
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• pp.449-455
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• 2012

During the measurement of the flow rate of gases such as natural gas, flow hunting is observed in most orifice meters but the intensity of flow hunting at each metering system shows different characteristics. In order to investigate why such a difference occurs and whether the difference actually influences metering error, pipeline network analysis on the main factors and characteristics of flow hunting was carried out in a previous study. Following this, in this study, computational fluid dynamics (CFD) analysis was carried out to clarify the relation between flow instability and flow hunting and determine the factors influencing the orifice meter depending on the intensity of upward pressure fluctuation, time interval, and flow rate. Finally, we showed that the pressure hunting rate is a function of the ratio of the pressure difference before and after an orifice meter. On the basis of CFD analysis results, we also presented some major factors and relations influencing flow hunting.