• KIPS Transactions on Computer and Communication Systems
• /
• v.5 no.3
• /
• pp.55-70
• /
• 2016

The most critical research issue in MANET environment is on supporting reliable communication between various devices. Various Multi-Hop Routing Protocol studies have proceeded. However, some problems you might have found when you use the existing link state routing technique are that it increases Control Message Overhead and it is unstable when node moves in CR circumstance which has transformation of using channel and MIMC circumstance which uses a number of interfaces. This essay offers a technique which is based on On-Demand Hello and the other technique which used Broadcast Interface of optimization as a solution to decrease Control Message Overhead. Also it proposes Quick Route Restoration technique which is utilized by GPS and MPR Selection technique which consider mobility as a solution of stable communication when node moves. Those offered Routing Protocol and OPNET based simulator result will be expected to be an excellent comparison in related research fields.

• KIPS Transactions on Computer and Communication Systems
• /
• v.3 no.6
• /
• pp.197-208
• /
• 2014

In an information society, privacy protection is one of the most important ethical issues. In medical institutes in which personal medical information is collected and stored, in addition, a privacy breach can cause a serious damage on personal lives. This study attempted to develop privacy concern measurement tool in personal medical information to measure patients' concern on their medical information from medical service consumers' perspective and verify its validity. For this, privacy concern measurement tool in personal medical information was developed based on the results of previous studies. After performing Exploratory Factor Analysis(EFA) and Confirmatory Factor Analysis(CFA) on the measurement tool, its reliability and validity were verified. It appears that the measurement tool would be useful in developing decent privacy protection policy after investigating citizens' concern on the protection of personal medical information and domains they are interested in. For medical institutes as well, they would be helpful in coming up with a reasonable plan after figuring out problems in the protection of personal medical information and current status.

• KIPS Transactions on Computer and Communication Systems
• /
• v.2 no.3
• /
• pp.111-116
• /
• 2013

With technology scaling, soft error rate has greatly increased in embedded systems. Due to high performance and low power consumption, VLIW (Very Long Instruction Word) architectures have been widely used in embedded systems and thus many researches have been studied to improve the reliability of a system by duplicating instructions in VLIW architectures. However, existing studies have ignored the feature, called VLES (Variable Length Execution Set), which is adopted in most modern VLIW architectures to reduce code size. In this paper, we propose how to support instruction duplication in VLIW architecture with VLES. Our experimental results demonstrate that a VLIW architecture with VLES shows 64% code size decrement on average at the cost of about 4% additional cell area as compared to the case of a VLIW architecture without VLES when instruction duplication is applied to both architectures. Also, it is shown that the case with VLES does not cause extra execution time compared to the case without VLES.

• The Transactions of the Korea Information Processing Society
• /
• v.6 no.2
• /
• pp.274-281
• /
• 1999

Many popularly used recent high-sped and high-capacity disks use the Zone-Structured in which a disk consists of multiple zones. A zone-structured disk has multiple zones, and the bandwidth and the number of sectors in each zone are different from each other. When the previous studies that modeled disks based on the assumption that the number of sectors in all tracks are same are applied to the zone-structured disk and the video data stored in a round-robin manner are read out with the SCAN technique, the transfer rate of the disk is fixed with that of the innermost zone. And excessive disk space is wasted either. To resolve the problem, this paper proposes a method for reconstructing the physical zones into logical zones by split and merge operations and develops a method for determining optimum transfer block size.

• Journal of Power Electronics
• /
• v.15 no.2
• /
• pp.455-468
• /
• 2015

A microgrid (MG) with integrated renewable energy resources can benefit both utility companies and customers. As a result, they are attracting a great deal of attention. The control of a MG is very important for the stable operation of a MG. The droop-control method is popular since it avoids circulating currents among the converters without using any critical communication between them. Traditional droop control methods have the drawback of an inherent trade-off between power sharing and voltage and frequency regulation. An adaptive droop control method is proposed, which can operate in both the island mode and the grid-connected mode. It can also ensure smooth switching between these two modes. Furthermore, the voltage and frequency of a MG can be restored by using the proposed droop controller. Meanwhile, the active power can be dispatched appropriately in both operating modes based on the capacity or running cost of the Distributed Generators (DGs). The global information (such as the average voltage and output active power of the MG and so on) required by the proposed droop control method to restore the voltage and frequency deviations can be acquired distributedly based on the Multi Agent System (MAS). Simulation studies in PSCAD demonstrate the effectiveness of the proposed control method.

• Journal of Korea Water Resources Association
• /
• v.35 no.6
• /
• pp.797-805
• /
• 2002

The EV ROM, a joint reservoir operation model for flood control that accounts for the downstream flow condition, has been introduced in the preceding article (Shin et al, 2000). A joint reservoir operation model computer program for the Geum river basin, developed by FORTRAN Power Station 4.0 using the EV ROM, is hereby presented. Three case studies of flood control by joint operation of the Yongdam and Daechung Multipurpose Dams in the Geum river basin revealed that the performance of the EV ROM was superior to the existing Rigid ROM and Technical ROM. This is because the EV ROM can account for the downstream flow condition as well as the upstream inflow and the reservoir water level. In order to apply for various floods events in the future, consistent improvement of the developed EV ROM and efforts for more accurate rainfall prediction are required.

• Radiation Oncology Journal
• /
• v.16 no.4
• /
• pp.357-366
• /
• 1998

Brachytherapy is an essential part of radiotherapy for uterine cervical cancer. The low dose rate (LDR) regimen has been the major technique of intracavitary therapy for cervical cancer. However, there has been an expansion in the last 20 years of high dose rate (HDR) machines using Ir-192 sources. Since 1979, HDR brachytherapy has been used for the treatment of uterine cervical cancer in Korea. The number of institutions employing HDR has been increasing, while the number of low dose rate system has been constant. In 1995, there was a total 27 HDR brachytherapy units installed and 1258 cases of patients with cervical cancer were treated with HDR Most common regimens of HDR brachytherapy are total dose of 30-39 Gy at point A with 10-13 fractions in three fractions per week. 24-32 Gy with 6-8 fractions in two fractions per week, and 30-35 Gy with 6-7 fractions in two fractions per week. The average fractionation regimen of HDR brachytherapy is about 8 fractions of 4.1 Gy each to Point A. In Korea, treatment results for HDR brachytherapy are comparable with the LDR series and appears to be a safe and effective alternative to LDR therapy for the treatment of cervical carcinoma. Studies from the major centers report the five-year survival rate of cervical cancer as. 78-86$\%$ for Stage 1, 68-85$\%$ for stage 11, and 38-56$\%$ for Stage III. World-wide questionnaire study and Japanese questionnaire survey of multiple institutions showed no survival difference in any stages and dose-rate effect ratio (HDR/LDR) was calculated to be 0.54 to 0.58. However the optimum treatment doses and fractionation schemes appropriate to generate clinical results comparable to conventional LDR schemes have yet to be standardized. In conclusion, HDR intracavitary radiotherapy is increasingly practiced in Korea and an effective treatment modality for cervical cancer. To determine the optimum radiotherapy dose and fractionation schedule, a nation-wide prospective study is necessary in Korea. In addition, standardization of HDR application (clinical, computer algorithms, and dosimetric aspects) is necessary.

• Journal of KIISE:Information Networking
• /
• v.29 no.2
• /
• pp.141-155
• /
• 2002

A medium access control protocol is proposed for integrated voice and data services in the packet CDMA network with a small coverage. Uplink channels are composed of time slots and multiple spreading codes for each slot. This protocol gives higher access priority to the delay-sensitive voice traffic than to the data traffic. During a talkspurt, voice terminals reserve a spreading code to transmit multiple voice packets. On the other hand, whenever generating a data packet, data terminals transmit a packet based on the status information of spreading codes in the current slot, which is received from base station. In this protocol, voice packet does not come into collision with data packet. Therefore, this protocol can increase the maximum number of voice terminals.

• KIPS Transactions on Computer and Communication Systems
• /
• v.3 no.12
• /
• pp.463-478
• /
• 2014

Portal site is not only providing search engine and e-mail service but also various services including blog, news, shopping, and others. The fact that average number of daily login for Korean portal site Naver is reaching 300 million suggests that many people are using portal sites. With the increase in number of users followed by the diversity in types of services provided by portal sites, the attack is also increasing. Most of studies of password authentication is focused on threat and countermeasures, however, in this study, we analyse the security threats and security requirement of membership, login, password reset first phase, password reset second phase. Also, we measure security score with common criteria of attack potential. As a result, we compare password authentication system of domestic and abroad portal sites.

• KIPS Transactions on Computer and Communication Systems
• /
• v.3 no.12
• /
• pp.455-462
• /
• 2014

In recent years, various services in mobile environments due to the growth of mobile devices and related techniques like wireless networks. Furthermore, as the increasing communication traffic in cellular networks has become a new significant issue, many studies for device-to-device(D2D) communication and D2D-based cooperative services have been performed recently. In this paper, we design a smart agent system for D2D-based cooperative services and propose a dynamic service binding method based on service ontology. We classify roles of mobile devices for cooperative services by defining three types of smart agents, and construct a knowledge base in order to describe properties of 'service' unit. The proposed knowledge model, D2D cooperative service ontology, can enable a autonomous cooperative services between mobile devices by binding a requested service to the appropriate member device according to the real-time context in mobile environments.