• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.459-464
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• 2007

Resolution 122 requires to study power limitation applicable for HAPS ground stations to facilitate sharing with space station receivers in 47/48GHz bands. ITU-R Recommendation 1481-1 recommends to improve the side lobe characteristics of HAPS ground station antenna for frequency sharing between FSS system and HAPS system. In this paper, we propose the maximum allowable off-axis e.i.r.p. level of HAPS ground station antennas by considering power limitation to HAPS ground station in Resolution 122, and by improving the side lobe characteristics of HAPS ground station antennas in Recommendation SF.1481-1. The simulation results show that the unfeasible sharing distance between HAPS ground station and FSS earth station can be reduced remarkably, and give the possibility of frequency sharing between two above systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.95-98
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• 2009

RFID(Radio Frequency IDentification) technology is an automatic identification method using radio frequencies between RFID reader which collects the informatin and tag which transmits the information. RFID technology develops passive RFID which transmit the only ID to active RFID which transmit the additional information such as sensing information. there is ISO/IEC 18000-7 as typical standard of active RFID. it is single channel system of 433.92MHz and has limitation of collection of a number of tags. to overcome limitation of collection of many tags, we propose the new 2.4GHz active RFID technology which can use the multi-channel. if reader has multi-interface and uses another channel in each, reader could fast collect the tags. but, if a reader which has many interfaces collects tags through the specific interface, the performance may not improve any more comparing with a reader using single interface. in this paper, we show the fast collection through design and implementation of protocol for load balancing between interfaces in multi-interface RFID reader.

• Journal of the Korean Society for Railway
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• v.19 no.4
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• pp.445-455
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• 2016

A goal of the Real-time railway safety supervision system is to improve the safety oversight efficiency and to prevent accidents by integrating existing distributed monitoring systems, train, signal, power and facilities. So, the system require better performance regarding real-time processing based on big data. The disk-based database that is used in existing railway control systems has a problem with real-time processing; memory-based databases haves a limitation in terms of big-data processing; and time series databases haves a limitation in terms of real-time processing. So, we need a new database architecture for simultaneous real-time processing based on big data. In this study, we review the existing railway monitoring systems and propose a new database architecture for a real-time railway safety supervision system.

• Journal of the Korean Geophysical Society
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• v.5 no.1
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• pp.63-71
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• 2002

The integral equation method is a powerful tool for electromagnetic numerical modeling. But the difficulty of this technique is the size of their linear equations, which demands excessive memory and calculation time to invert. This limitation of the integral equation method becomes critical in inverse problem. To overcome this limitation, a lot of approximation and series methods, such as conventional Born, modifed Born and extended Born, were developed. But all the methods need volume integration of Green tensor, which is very time consuming. In electromagnetic theory, Green tensor rapidly decreases as the distance between source and field cell increases. Therefore, the source cell which are far away from the field cell does not make an effect on the electric field of the field cell. Consequently, by ignoring the effect of Green tensor due to far away source cells, computing time for electromagnetic numerical modeling can be reduced dramatically. Comparisons of this new method against a full integral equation, extended Born approximation and series code show that the method is accurate enough much less time consuming.

• Annals of Surgical Treatment and Research
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• v.95 no.5
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• pp.233-239
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• 2018

Purpose: In Korea, the working-hour limitation regulation has been implemented in December 2017. We aimed to define the difference in operative experience of surgical residents before and after implementing this policy in 2 hospitals among 8 affiliated hospitals of the Catholic Medical Center where implemented the 80 working-hour limitation policy since March 2015. Methods: All the operation records were reviewed, and the number of resident-participated surgeries between March and August in 2002 and 2017 were compared. Operations performed or participated in by residents as first assistants were defined as resident participated surgery. Results: After 2 years from the initiation of the resident work-hour limitations, the number of resident participated surgery has slightly decreased in both hospitals (Yeouido St. Mary's Hospital [YSM]: 317 to 302, St. Paul Hospital [SPH]: 635 to 461). For each resident, changes were like followings: $0{\rightarrow}21$ cases for R1, $65{\rightarrow}72$ cases for R2, $83{\rightarrow}192$ cases for R3, and $169{\rightarrow}17$ cases for R4 in YSM. In SPH, number of resident participating surgery was changed like followings: $4{\rightarrow}32$ cases for R1, $222{\rightarrow}100$ cases for R2, $317{\rightarrow}300$ cases for R3, and $92{\rightarrow}29$ cases for R4. In both hospital, while, total number of resident participating oncologic surgery has been decreased, number of resident participating appendectomy has been far increased. Activity of each grade resident is different according to hospital. Conclusion: Although total number of resident participating surgery decreased, variable changes were observed in each grade of resident according to each type of surgery and different hospitals. It is believed that comparisons of experiences from more hospitals in the future would be helpful in establishing the guidelines for surgical experience requirement of residents in Korea.

• International Area Studies Review
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• v.15 no.2
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• pp.451-481
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• 2011

This study is the identify of influence in the social adjustment stress on foreign female immigrants in Korea. the study is like followings: First, offering the opportunity of employment will increase social activity of foreign female immigrants in Korea, and it will be helpful for their adaptation in Korean society. Second, the service of supporting family should be provided for settlement of foreign female immigrants in Korea, and proper education for affirmative adaptation of them in all spheres of home life, language, culture and it should be performed through their family. Third, systematic service of social welfare should be offered. The adoption of the system which overcome geographical limitation and can provide the service to needed people is required. In addition, for foreign female immigrants in Korea who cannot receive basic Korean language's education because of geographical limitation, it will be another solution which creates programs about Korean language's education. Finally, for understanding culture shock and keeping social relationship, the plans of supporting foreign female immigrants in Korea are required.

• Journal of vocational education research
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• v.37 no.2
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• pp.1-18
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• 2018

Recently human resources who have core competencies are regarded as an important factor in the labor market. However, there are few limitation about instruments to measure university students' core competencies. Recognizing this limitation, this study aimed to develop and validate the tests that could measure core competencies of students in universities. Among NCS core competencies, this study primarily focused on the self-development skill, organizational skill and resources management skill. This study concluded the proper definition of core competencies for university students, sub factors of 3 domains and questionnaire and validated its measurement. Implications of this study were discussed.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.75-80
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• 2019

Oilseed rape is known to crop having low nitrogen use efficiency (NUE) but requires high levels of N fertilizer. NUE is associated with N remobilization from source to sink organ, consequently affects seed yield. Remobilization of leaf N is also related to transport of C/N metabolites in phloem. However, interaction between seed yield and phloem transport was not fully documented. In response to seed yield, N and C metabolites and their transport into seed from bolting to pod filling stage investigated in two contrasting genotypes (Capitol and Pollen) cultivated under ample (HN) or limiting nitrate (LN) supply. Seed yield was significantly reduced in N limitation and its reduction rate was much lower in Capitol than in Pollen compared to HN treated plants. Amino acid and protein content was higher in Capitol than in Pollen at bolting stage. They gradually decreased during plant development but not significant between two cultivars and/or two treatments. Glucose, fructose and sucrose content were 1.8-,1.6- or 1.25-fold higher in LN condition than in HN condition, respectively. Amino acid and sucrose content in phloem were largely higher in Capitol than in Pollen under LN condition. These results indicate that the higher seed yield might be related to greater transport ability of amino acid and sucrose in phloem under LN condition.

• The Journal of Fisheries Business Administration
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• v.50 no.2
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• pp.1-21
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• 2019

This study is to excavate superior fishing communities by applying the Ostrom (1990)'s principles of sustainable and successful use of common goods. Ostrom(1990)'s principles are (1) clearly defined boundaries (2) congruence between appropriation and provision rules and local conditions, (3) collective choice arrangements (4) monitoring (5) graduated sanctions (6) conflict-resolution mechanism (7) recognition of rights to organize by external government authorities (8) nested enterprises. The survey was carried out under the individual interview method of 15 fishing village members in 32 fishing communities with the government's fishery environment improvement and fishery creation projects. The total effective samples are 477. These data were analyzed. The analysis result shows that 24 fishing villages are selected among the 32 fishing communities in the samples, including Nanji, Sanghwang, Songseok, Sinshido, Jukyo, Jinsan, Changli, Pado, Beopsan, Rahyang, Palbong, Woongdo, Daehwang, Sapsi, Chido, Jinri, Daeri, Songgak, Joongwang, Ojii, Doripo, Doseong, Mongsan 1ri and Songnim as superior fishing villages. The results of this study have limitation that may vary depending on the rigor of the criteria in the process of deriving good fishing communities. Despite this limitation, this study has expanded existing research focused on validating the theoretical applicability of the framework through case analysis of specific fishing communities to objectively and quantitatively to many fishing communities. The results of this study are expected to contribute to the creation of conditions in which fishermen can continue to manage their fishing grounds and stand on their own feet by presenting the framework and principles for developing desirable fishing village models for the continued use of mudflat shells grounds as the common goods.

• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.132-147
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• 2015

In this article, the research trends regarding the analysis and restoration of the pigments applied on colored cultural properties during past 25 years are reviewed and the future research direction in this field of study is proposed. There are over 100 different pieces of the colored cultural property samples that have been analyzed in Korea during the time and are increasing numbers of studies on comparative investigations as well. In addition, new analysis techniques have been introduced to surpass the limitation of the current analysis techniques and the database construction has been developed tremendously, which will enhance the analysis reliability, indicating fast growth in the related research areas. There are also studies on finding new materials to replace the traditional ingredients for producing color pigments and related other materials to overcome the limitation of the traditional ingredients on top of the steady number of studies on reproduction and restoration of the traditional pigments. These various research efforts will bring much development in this area of research. One suggestion to be made is that there need to be long term planned research works for certain type of studies. For instance, the effect to the colored cultural properties due to the environmental change is one of important research topics that should be carefully studied, which requires longer time period and also more patience than the research works in the current and past trends.