• Korean Journal of Digital Imaging in Medicine
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• v.10 no.2
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• pp.23-31
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• 2008

Computed radiography(CR) has been widely used in the field of diagnostic radiography since digital X-ray image was introduced. The imaging performance of CR system was studied by analyzing the digital image data of the CR images which are the outcomes of the whole imaging system composed of image plate(IP), laser digitizer, analoge-digital convertor, and a given image processing unit. In this study, we used a conventional CR system made by Agfa. From the flat field image of 150$\times$150 image pixels, signal-to-noise ratio(SNR) was calculated. SNR of the CR image increases in proportion to logarithm value of the X-ray exposure irradiated on the IP. SNR is less than about 6 at the exposure below 0.2mR and is more than 10 at the exposure above 0.54mR. In our study, most of images obtained by the smaller exposures less than 2.0mR can not be readable. In general, the minimum value of the SNR ranges from 3 to 5. We obtained modulation transfer function(MTF) by analyzing the bar pattern image which was made under conditions as follows: X-ray tube potential was 55kVp, the IP exposure was 0.54 mR, and the distance between X-ray source to IP was 2m, where bar pattern was located on the IP. MTF is 23% at 2.5lp/mm spatial frequency. Provided that the MTF of noise equivalent modulation is 10%, the CR system has the limiting spatial resolution of 3.2lp/mm. If the image sharpness is evaluated by the spatial frequency where MTF is 50%. the corresponding spatial frequency is 0.5$\sim$0.75lp/mm. MTFA(Modulation Transfer Function Area) is 1.0lp/mm. Compared with the Fuji CR whose MTFA is 1.1lp/mm, Agfa CR in this study shows almost same MTFA performance.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.35-40
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• 2015

An IP-2 type container is used for the transport of low-level radioactive materials. An IP-2 type metal container was modeled and analyzed for the dropping conditions in normal transport conditions required by NSSC Notice 2014-50, "Regulations on the packaging and transport of radioactive materials." Structural analyses were performed by finite element method, and the acceptability was reviewed by comparing the results with technical standards and maximum allowable stresses of each material. Structural members of the container were modeled as 3D solid elements, and the possible dropping directions were considered in these analyses. Results show that maximum stresses, maximum deformed gaps in the cover, and maximum estimated thickness reduction in structural members were well below the allowable limits; thus, the structural integrity of the container was confirmed.

• Proceedings of the KAIS Fall Conference
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• 2002.05a
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• pp.151-154
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• 2002

반도체 소자의 기판 재료로 사용되고 있는 실리콘 웨이퍼는 그 정밀도가 매우 중요하다. 본 연구에서는 균일한 Dopant 농도 분포를 얻을 수 있는 중성자 변환 Doping을 이용하여 실리콘에 인(P)을 Doping하는 연구를 수행하였다. 중성자 변환 Doping, 즉 NTD(Neutron Transmutation Doping)란 원자번호 30인 실리콘 동위원소에 중성자가 조사되면 원자번호 31인 실리콘으로 변환되고, 2.6시간의 반감기를 갖고 decay 되면서 인(P)으로 변하게 되어 실리콘 웨이퍼에 n-type 전도를 갖게 하는 것을 말한다. 본 연구에서는 하나로 원자로를 이용하여 고저항(1000-2000Ωcm) FZ 실리콘 웨이퍼 에 두 개의 조사공에서 중성자 조사하여 저항의 변화를 관찰하였고, 중성자 조사시 발생하는 점결함을 분석하여 점결함이 저항 변화에 미치는 영향을 알아보았다. 중성자 조사 전 이론적 계산에 의해 HTS조사공은 5Ωcm, 20.1Ωcm 이고 IP3조사공은 5Ωcm, 26.5Ωcm, 32.5Ωcm 이었고, 중성자 조사 후 SRP로 측정한 결과 실제 저항값은 HTS-1 2.10Ωcm, HTS-2 7.21Ωcm 이었고, IP-1은 1.79Ωcm, IP-2는 6.83Ωcm, 마지막으로 IP-3는 9.23Ωcm 이었다. DLTS 측정 결과 IP조사공에서 새로운 피의 결을 발견할 수 있었다.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.46-57
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• 2000

Ongoing standardization effort on 3G cellular system in 3GPP (UNTS) is based on GPRS core network and promises a global standard for systems capable of offering ubiquitous access to internet for mobile users. Considered radio access systems(FDD CDMA, TDD CDMA, and EDGE) are optimized for robust mobile use. However, there are alternative relatively high-rate radio interfaces being standardized for WLAN (IEEE802.11 and HIPER-LAN/2) which are capable of delivering significantly higher data rates to static or semi-static terminals with much less overhead. Also WPANs(BLUETOOTH, IEEE802.15), which will be present in virtually every mobile handset in the near future, are offering low cast and considerable access data rate and thus are very attractive for interworking scenarios. The prospect of using these interfaces as alternative RANs inthe modular UMTS architecture is very promising. Additionally, the recent inclusion of M-IP in the UMTS R99 standard opens the way for IP-level interfacing to the core network. This article offers an overview into WLAN-Cellular interworking. A brief overview of GPRS, UMTS cellular architectures and relevant WLAN standards is given. Possible interworking architectures are presented.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.195-201
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• 2008

We proposed that is suitable network environment and wire/wireless communication network, easy of implementation, security level preservation, scalable & reconfigurable to TCP/IP protocol architecture to implement suitable smart card MS-Serpent cryptographic algorithm for smart card by hardware base chip level that software base is not implement. Implemented MT-Serpent cryptosystem have 4,032 in gate counter and 406.2Mbps@2.44MHz in throughput. Implemented MS-Serpent cryptographic algorithm strengthens security vulnerability of TCP/IP protocol to do to rescue characteristic of smart card and though several kind of services are available and keep security about many user in wire/wireless environment, there is important purpose.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.752-757
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• 2016

Machine to Machine (M2M) communications is communications between a business application and devices via a communication network without any direct human interaction. The aim of our research is to connect any M2M device with an M2M AS (Application server) through an IMS (IP Multimedia Subsystem) Network Core using a M2M Gateway, in order to develop an M2M Horizontal Services Platform over IMS. An IP Multimedia Subsystem (IMS) is an architectural framework defined by the wireless standards body of the 3rd Generation Partnership Project (3GPP) for delivering IP multimedia services to mobile users. This paper shows the design and implementation of a Horizontal M2M Network Services Platform over an IP Multimedia Subsystem (IMS) using the Message Session Relay Protocol (MSRP). We summarize the protocols and architectures that formed the basis for the creation of our architecture. We provide a detailed description of our architecture design, describing the call flow of the proposed architecture and the entities operating in each process. We also describe the design and implementation process detailing the different tools used, explaining the selection of each component and its importance; also how we designed and implemented the M2M gateway, M2M Application Server, Open IMS Core, business application and M2M devices.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12A
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• pp.991-1001
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• 2003

CCFH(Candidatecasting Fast Handoff) algorithm excels the performance of existing fast handoff schemes using multicasting in terms of handoff latency and B/W efficiency. The scheme uses L2 information(BSSID) at Wireless LAN and starts multicasting before L2 handoff. So it can reduce L3 handoff latency. At this article, we would show that Candidatecasting Fast Handoff Scheme is clearly new scheme using L2 information and has the good performance.

• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.56-65
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• 2007

For supporting seamless service in NGN, various schemes for mobility are studying in ITU-T, 3GPP, IETF, and so on. Currently, mobility support schemes such as MIPv6, IP2, Q.MMF, IMS was introduced. However the performance analysis and comparison of all existing schemes is not examined as yet. That is, the existing mobility methods need to be compared according to same performance parameter. So, in this paper, we investigate and compare the performances of MIPv6, IP2, Q.MMF on latency during location registration. The latency in location registration is consider as cost and time. Then, the performance analysis of Q.MMF Case1 has shown the best performance as it is measured the minimum cost and time. Q.MMF Case1 is the location registration process in case that MT moves within a local network. As LLM in a access network manages the location of MT in this case, Q.MMF Case1 has lower location cost and time than other cases.

• Journal of the Korea Society of Computer and Information
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• v.17 no.5
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• pp.21-28
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• 2012

Recently, the necessity for good techniques of detecting network traffic attack has increased. In this paper, we suggest a new method of detecting abnormal patterns of network traffic data by visualizing their IP and port information into two dimensional images. The proposed approach first generates four 2D images from IP data of transmitters and receivers, and makes one 2D image from port data. Analyzing those images, it then extracts their major features such as linear patterns or high intensity values, and determines if traffic data contain DDoS or DoS Attacks. To comparatively evaluate the performance of the proposed algorithm, we show that our abnormal pattern detection method outperforms the existing algorithm in terms of accuracy and speed.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6165-6169
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• 2014

Background: The advantage of intra-peritoneal (IP) chemotherapy (CT) in the initial management of ovarian cancer after cytoreductive surgery is well known. The feasibility and toxicity of a treatment regimen with an IP + intravenous CT (IPIVCT) for optimally debulked stage III ovarian cancer were here evaluated retrospectively. Materials and Methods: A total of 30 patients were treated in our institution between October 2006 and February 2011. Patients received IV paclitaxel $175mg/m^2$ over 3 hours followed by IP cisplatin $75mg/m^2$ on day 1; they also received IP paclitaxel $60mg/m^2$ on day 8. They were also scheduled to receive 6 courses of CT every 21 days. Results: The median age of the patients was 55 years (35-77), and the majority had papillary serous ovarian cancer (63.3%). The patients completed a total of 146 cycles of IPIVCT. Twenty-eight were able to receive at least three cycles of IPIVCT and 18 (60%) completed the scheduled 6 cycles. Two patients discontinued the IPIVCT because of toxicity of chemotherapy agents and 6 had to stop treatment due to intolerable abdominal pain during IP drug administration, obstruction and impaired access. Grade 3/4 toxicities included neutropenia (6 patients; 20%), anemia (2 patients; 6.7%) and nausea-vomiting (2 patients; 6.7%). Doses were delayed in 12 cycles (8%) for neutropenia (n=6), thrombocytopenia (n=3) and elevated creatinine (n=3). Drug doses were not reduced. The median duration of progression-free survival (PFS) was 47.7 months (95%CI, 38.98-56.44) and overall survival (OS) was 51.7 months (95%CI, 44.13-59.29). Two and five-year overall survival rates were 75.6 % and 64.8%, respectively. Conclusions: IPIVCT is feasible and well-tolerated in this setting. Its clinically proven advantages should be taken into consideration and more efforts should be made to administer IPIVCT to suitable patients.