• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.12 no.4
• /
• pp.630-643
• /
• 2001

In this paper, the performance of a Multi-Carrier DS-CDMA system with Hybrid $SC/MRC- L_{c}/L$ diversity in the multipath Rayleigh fading environment is analyzed and compared with that of a Wideband DS-CDMA system. Each carriers of the number of the input diversity branches in the Multi-Carrier DS-CDMA system is L and among L, the branches of $L_c$ are chosen to be maximum-ratio-combined. And the diversity outputs are coherent-detected and despread by the correlator of each carrier. As the result, we have known that the structure of the Wideband DS-CDMA system with Hybrid $SC/MRC-L_{c}/L$ diversity reception becomes simple due to no synchronization of bit or phase and in terms of the error performance, the performance of Hybrid $SC/MRC- L_{c}/L$ diversity is better than that of selection diversity, but worse than that of MRC diversity. Moreover, the performance of a Multi-Carrier DS-CDMA system is better than that of a Wideband DS-CDMA system in multipath Rayleigh fading channel since Hybrid $SC/MRC- L_c/L$ diversity can obtain gain from each diversity branch. In case four carriers are used and required BER is $10^{-6}$ in wireless data communication, Hybrid SC/MRC-2/4 diversity can increase more 17 users than Hybrid SC/MRC-2/3 diversity because the better input branches can be selected through increase of input branches.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.26 no.4
• /
• pp.253-258
• /
• 2016

This paper proposes a method that utilizes optimization approach for localization of an indoor mobile robot. Bayesian filters which have been widely used for localization of a mobile robot use many control parameters to take the uncertainties in measurement and environment into account. The estimation performance depends on the selection of these parameter values. Also, the performance of the Bayesian filters deteriorate as the non-linearity of the motion and measurement increases. On the other hand, the optimization approach uses fewer control parameters and is less influenced by the non-linearity than the Bayesian methods. This paper compares the localization performance of the proposed method with the performance of the extended Kalman filter to verify the feasibility of the proposed method. Measurements of ranges from beacons of ultrasonic satellite to the robot are used for localization. Mahalanobis distance is used for detection and rejection of outlier in the measurements. The optimization method sets performance index as a function of the measured range values, and finds the optimized estimation of the location through iteration. The method can improve the localization performance and reduce the computation time in corporation with Bayesian filter which provides proper initial location for the iteration.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.21 no.9
• /
• pp.1777-1787
• /
• 2017

Federated authentication (FA) is a multi-domain authentication and authorization infrastructure that enables users to access nationwide R&D resources with their home-organizational accounts. An FA-enabled user is redirected to his/her home organization, after selecting the home from an identity-provider (IdP) discovery service, to log in. The discovery service allows a user to search his/her home from all FA-enabled organizations. Users get troubles to find their home as federation size increases. Therefore, a discovery service has to provide an intuitive way to make a fast IdP selection. In this paper, we propose a discovery system which leverages geographical information. The proposed system calculates geographical proximity and text similarity between a user and organizations, which determines the order of organizations shown on the system. We also introduce a server redundancy and a status monitoring method for non-stop service provision and improved federation management. Finally, we deployed the proposed system in a real service environment and verified the feasibility of the system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2016.05a
• /
• pp.685-688
• /
• 2016

SBAS(Satellite Based Augmentation System) broadcasts the correction message based on satellite communication to improve the positioning accuracy of GNSS user. For this reason, SBAS is actively being utilized on navigation part. To apply SBAS to navigation part, it should satisfy not only accuracy but also integrity, continuity, availability, coverage requirements and so on. Since SBAS reference station is the base infrastructure of SBAS, it is the main factor to determine the environment, position, and geometry of reference stations to achieve SBAS service performance. Therefore, a site environmental analysis should be performed prior to the selection of SBAS reference station. In this paper, it performs the environmental analysis of NDGPS(Nationwide Differential GPS) reference station sites on the premise that SBAS reference station will be co-operated in the same site of NDGPS operated by MOF(Ministry of Oceans and Fisheries). The environmental analysis is conducted as carrying out the visibility analysis of GPS satellite and interference analysis. This paper also presents the brief procedures and requirements for site survey of SBAS reference station.

• The KIPS Transactions:PartD
• /
• v.14D no.2
• /
• pp.265-272
• /
• 2007

In this paper, we implement an automated composition system of web services using hybrid techniques that merge the benefit of BPEL techniques, with the advantage of OWL-S, BPEL techniques have practical capabilities that fulfil the needs of the business environment such as fault handling and transaction management. However, the main shortcoming of these techniques is the static composition approach, where the service selection and flow management are done a priori and manually. In contrast, OWL-S techniques use ontologies to provide a mechanism to describe the web services functionality in machine-understandable form, making it possible to discover, and integrate web services automatically. This allows for the dynamic integration of compatible web services, possibly discovered at run time, into the composition schema. However, the development of these approaches is still in its infancy and has been largely detached from the BPEL composition effort. In this work, we describe the design of the SemanticBPEL architecture that is a hybrid system of BPEL4WS and OWL-S, and propose algorithms for web service search and integration. In particular, the SemanticBPEL has been implemented based on the open source tools. The proposed system is compared with existing BPEL systems by functional analysis. These comparisions show that our system outperforms existing systems.

• Management & Information Systems Review
• /
• v.39 no.3
• /
• pp.53-82
• /
• 2020

Daejeon Metropolitan City has the best innovation capability infrastructure (ICT) required for the 4th industry. Nevertheless, there are scattered factors that hinder the industrial ecosystem. In this study, the factor of job creation was approached from the viewpoint of organizational ecology in consideration of regional characteristics during the 4th Industrial Revolution.That is, the case of job creation through overseas ICT-based clusters (or cities) was examined. Then, the factors of organizational ecology, 'niche', 'variation', 'selection', and 'retention' were derived. Through this process, we explored the environment surrounding Daejeon Metropolitan City and benchmarked lessons from existing overseas cluster cases. As a result, we discover the 'niche' of ICT-based job creation and suggest strategies for the 'variation' process to survive in the ecosystem and how to be 'retention' in the ecosystem. n conclusion, the strategy of the organizational ecological approach to establish itself as a metropolitan city as the strength of Daejeon city and the 'innovation hub' that is evident, such as '4th Industrial Revolution City', 'Innovation City Designation', and 'Secure Excellent Capability of SW' Insist on need. Through this study, we hope that there will be a theoretical contribution to the prior research lacking from original research such as the scarcity of ICT-based job creation research in response to the era of the fourth industrial revolution, recognition of the importance of the region in job creation, and presentation of an organizational ecological approach of sustainable clusters.

• Korean journal of applied entomology
• /
• v.5_6
• /
• pp.47-54
• /
• 1968

In order to develop an effective control measure for the rice stripe disease, methods of testing for resistance and selection of resistant varieties among the leading varieties were investigated. For use as a parent in breeding for resistant variety to the disease, total of 410 rice varieties were tested. 1. Disease occurrence was higher at group inoculation than that of individual inoculation in comparing the inoculation methods. 2. In both methods, Lacrose responded susceptible; Zenith and St. No. 1 resistant, and the rest moderate. 3. Suseptible symptom type A was prevalant among the susceptible varieties, while resistant symptom type C was abundant among the resistant varieties, There was no difference between the inoculation methods. 4. 410 rice varieties tested could he divided into 3 groups as susceptible (21 varieties), moderate (377 varieties) and resistant (12 varieties). Resistant varieties wers St. No. 1 and 2, Shin-2, Gulfrose Bonnet, Arkrose, Sun Bonnet, Zenith, Yeechunchilichal, Norm-24, Opaikjoke, Yangchubatchal and Nonglimana-1, Nams-97,-149, -159, -216. -265, Iri-243, -265, Kanchuk -5, -7, -8, -10, -41, -43, -47, -50, Suwon-56, -77, Norin-22, Cod-4. Lacrose and Chukna were susceptible. 5. There was slight differance in the disease occurrence in regard to maturing period. However late varieties seem to be more resistant than early or medium varieties. The medium varieties seem to be susceptible. Most of the introduced varieties from foreign countries and the upland cultivated varieties were resistant. 6 Among the leading varieties, Shin-2 in Kangwon-Do was resistant, Kosi in Choongchung-Do, was susceptible, aad the others were moderate.

• Journal of The Korean Association For Science Education
• /
• v.37 no.4
• /
• pp.679-691
• /
• 2017

Despite the growing importance of socio-scientific issues (SSI), little work has focused on teachers' pedagogical knowledge, and few studies have examined how in-service teachers use and apply SSI-related instructional methods and strategies. Consequently, the purpose of this study was to explore how science teachers with lots of SSI teaching experience determined teaching orientation, selected and revised instructional methods, and devised assessments in science classroom. We used a case study approach aimed at a deep description of these teachers' teaching experiences and employed semi-structured and in-depth interviews with five experienced teachers. Our findings indicate that teaching orientation and learning objectives seemed to influence the selection and modification of instructional strategies and methods. In addition, students' learning experiences or classroom environment were considered and modified in light of achieving these learning objectives. However, introducing SSI into the classroom assessment is not seriously considered by most teachers. This study can provide teachers with useful information when designing and developing SSI classes, taking into account various aspects of the PCK such as learning orientation, instructional methods, learner expereince and curriculum standards.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2002.08a
• /
• pp.54-63
• /
• 2002

Post-harvest technology for rice was focused on in-bin drying system, which consists of about 100, 000 facilities in 1980s. The modernized Rice Processing Complex (RPC) and Drying Storage Center (DSC) became popular for rice dry, storage, process and distribution from 1990s. However, the percentage of artificial drying for rice is 48% (2001) and the ability of bulk storage is about 15%. Therefore it is necessary to build enough drying and bulk storage facilities. The definition of high quality rice is to satisfy both good appearance and good taste. The index for good taste in rice is a below 7% of protein, 17-20% of amylose, 15.5-16.5% of moisture contents and high concentration of Mg and K. To obtain a high quality rice, it is absolutely needed to integrate high technologies including breeding program, cropping methods, harvesting time, drying, storing and processing methodologies. Generally, consumers prefer to rice retaining below b value of 5 in colorimetry, and the whiteness, the hardness and the moisture contents of rice are in order of consumer preference in rice quality. By selection of rice cultivars according to acceptable quality, the periods between harvesting time and drying reduced up to about 20 days. Therefore it is necessary to develop a low temperature grain drying system in order to (1) increase the rate of artificial rice drying up to 85%, (2) keep the drying temperature of below 45C, (3) maintain high quality in rice and (4) save energy consumption. Bulk storage facilities with low temperature storage system (7-15C) for rice using grain cooler should be built to reduce labor for handling and transportation and to keep a quality of rice. In the cooled rice, there is no loss of grain quality due to respiration, insect and microorganism, which results in high quality rice containing 16% of moisture contents all year round. In addition, introducing a low temperature milling system reduced the percentage of broken rice to 2% and increased the percentage of head rice to 3% because of proper hardness of grain. It has been noted that the broken rice and cracking reduced significantly by using low pressure milling and wet milling. Our mission for improving rice market competitiveness goes to (1) produce environment friendly, functional rice cultivars, (2) establish a grade standard of rice quality, (3) breed a new cultivar for consumer oriented and (4) extend the period of storage and shelf life of rice during postharvest.

• Journal of Korea Water Resources Association
• /
• v.53 no.11
• /
• pp.939-949
• /
• 2020

Currently, the demand for farmland is steadily decreasing due to changes in the agricultural environment and dietary life. In line with this, the government adopted an integrated water management with the enactment of the Framework Act on Water Management on June 2019. Therefore, it is required to take a closer look at agricultural water demand that accounts for 61% of water use for efficient water resources management. In this study, the overal process was evaluated for estimating agricultural water demand. More specifically, agricultural water demand for paddy field, which comprises 67% to 87% of agricultural water demand, was reviewed in detail. The biggest issue in estimating the paddy field water demand is the selection of the method for potential evapotranspiration. FAO recommends Penman-Monteith, but, currently, our criteria suggest a modified Penman equation that shows over estimation. Also, the crop coefficient, which is the main factor in evaluating evapotranspiration, has an issue that does not consider the current climate and crop varieties because it was developed 23 years ago. Comparing the Modified Penman and Penman-Monteith equations using the data from Jeonju National Weather Service, the modified Penman equation showed a big difference compared to the Penman-Monteith equation. When the crop coefficient was applied, the difference between late May and late August increased, where the amount of evapotranspiration was high. The estimation process was applied to four study reservoirs in Gimje. Comparing the estimated water demand with the supplied water record from reservoirs, the results showed that the estimation accuracy depends on not just the potential evapotranspiration, but also the standard water storing level in paddy fields.