• Journal of IKEEE
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• v.14 no.1
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• pp.65-74
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• 2010

The Digital TV(DTV) standard has ushered in a new era in TV broadcasting and raised a great demand for DTV tuners. There are many challenges in designing a DTV tuner, of which the most difficult part is the frequency synthesizer. This paper presents the design of a frequency synthesizer for DTV Tuners in a $0.18{\mu}m$ CMOS process. It satisfies the DTV(ATSC) frequency band(54~806MHz). A scheme is proposed to cover the full band using only one VCO. The VCO has been designed to operate at 1.6~3.6GHz band such that the LO pulling effect is minimized, and reliable broadband characteristics have been achieved by reducing the variations of VCO gain and frequency step. The simulation results show that the designed VCO has gains of 59~94MHz(${\pm}$17.7MHz/V,${\pm}$23%) and frequency steps of 26~42.5MHz(${\pm}$8.25MHz/V,${\pm}$24%), and a very wide tuning range of 76.9%. The designed frequency synthesizer has a phase noise of -106dBc/Hz at 100kHz offset, and the lock time is less than $10{\mu}$sec. It consumes 20~23mA from a 1.8V supply, and the chip size including PADs is 2.0mm${\times}$1.8mm.

• Journal of the Korea Concrete Institute
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• v.18 no.4 s.94
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• pp.459-467
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• 2006

Recently, interest grew on the quality of aggregates following the diminution of primary resources from river as to grow construction demand and the low grade of nature sand like sea sand. Following, need is to diversify the supply sources of fine aggregates which are excessively relying on sea sand and urgency is to find as soon as possible aggregate resources that can substitute sea sand. On the other hand, various fine aggregates are utilized to produce concrete in the domestic construction fields. However, few studies have been systematically investigated on the effects of such fine aggregates on concrete properties. Therefore, this study examined the effects of comparatively widely used fine aggregates in the domestic construction fields on the quality of concrete through the analysis of the effects of such fine aggregates on the physical properties of fresh concrete and strength of hardened concrete. Results revealed that crushed sand degraded the fluidity and air entraining of concrete compared to natural aggregates like sea sand and river sand. Especially, the use of crushed sand exhibiting bad grain shape and grade was larger adverse effect on the physical properties of concrete. The type of fine aggregates appeared to have negligible influence on the strength for W/C of 55%, 45% while crushed sand decreased the strength for W/C of 35% compared to natural aggregates. It analyzed that the combination of crushed sand exhibiting bad grain shape and grade with natural aggregates improved the characteristics of fresh concrete and had negligible influence on the strength.

• Archives of design research
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• v.15 no.1
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• pp.171-180
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• 2002

This study analyzed the current state of interior design as a major at vocational high schools, colleges, and universities to improve their curricula. The questionnaires of students, teachers, and interior designers were collected and frequency distribution and mean were used to analyze the data. Result showed that the alloted times with major fields were high, but those with classes related to interior design were comparatively low at vocational school. Vocational schools did not seem to supply the systemic and qualified major equation for the students who wanted to engage in interior design fields. Therefore curricula reflecting the demand of designers working for interior design companies and students should be made. Additionally practical education contents based on interior design field and achievement of certification should be developed to vitalize the vocational school.

• Journal of the Korean association of regional geographers
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• v.8 no.3
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• pp.314-325
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• 2002

The aims of this study is to find the facts of regional inequality and to suggest the desirable location of educational facilities and its related policies through the analysis of the distributional characteristics of high schools in Daegu viewing from public service facilities. The results are as follows. As of 2000 year, there are 76 high schools in operation in Daegu. The number of private high schools is more than that of national public ones in terms of their founders, and the number of general high schools outnumbers that of vocational high schools by their operational types. As a whole, the distribution of schools in Daegu is closely related to the population distribution(redistribution). In case of high schools, it shows that there is severe unevenness between demand and supply of educational facilities per district. The regional inequality of school facilities is getting worse by transfer and new establishment; inter-district transfer is mainly caused by the redistribution of population while intra-district transfer is accelerated by the pressure on better use of land. Recently there is a tendency that schools are newly established by public sector(national public schools) rather than by private sector(private schools). And the predilection or avoidance of a certain area in the process of choosing the site for transfer or new establishment of schools lead to inequality of education opportunities per district. In conclusion, the educational facilities should firstly be placed in the practice of public service facilities in terms of public welfare as well as the convenience of residents and regional inequality. Consequently, both construction of new high schools and the relocation of existing high schools have to be further activated. To achieve them, the role of public actions is particularly more important than that of private ones.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.2
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• pp.141-147
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• 2012

The purpose of the study is the acquisitions of knowledge related in job searching from local companies and job seekers using data mining techniques. At the first step, for the study, we had selected the local companies their headquarters are located in Jeonbuk province. Then we had picked the graduating students out from the high schools, colleges, and universities in the same area as the job seekers. After the targeting of the sample, we had surveyed 560 local companies and 14 schools for the collecting of the preliminary data. As the result of the survey, we could collect 173 responses from the companies and 551 responses from the job seekers. At the second step using data mining, we had adapted the C5.0 algorithm to extract the inference rules. Then we had used the Visual Basic (VB) programming language to visualize the rules at the third step. At the fourth step, we transformed the inference rules into DB tables. At the final step, we had executed the rule inferences to support the development of the long-term human resources development (HRD) strategies. As the result of the study, we could suggest the helpful information to the HRD directors and job seekers in designing their strategies in managing their jobs and career development.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.5
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• pp.713-719
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• 2018

At present, Busan City has proposed various taxi industry development measures, but fundamentally there is a problem that the taxi supply is excessive compared to the demand. Therefore, this study tried to explore ways to activate the taxi reduction. We first identified problems with the taxi reduction program in Busan, and analyze thoughts of taxi operators and workers. As a result, difficulties in securing funding and lack of consent from a large number of stakeholders were identified as the first problem for current taxi reduction program. Second, both groups recognize the need for the taxi reduction, and taxi drivers are more willing to participate in the program. Third, the most important factor in determining to take the taxi reduction program was the amount of compensation. And to activate taxi reduction program, it is helpful for executives to improve their management conditions and for drivers to place reemployment.

• Journal of the Korean Data and Information Science Society
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• v.24 no.4
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• pp.763-771
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• 2013

Due to a decrease in the number of college prep students which was triggered by the low birth rate since 1990, it is predicted, beginning 2016, that the entrance quota for colleges will exceed the number of applicants for college admissions. This serious imbalance between supply and demand raises serious problems for the regional universities, many of which have already been struggling to recruit new students and even considered closing down the schools. In an effort to securing best high school students, many of the schools have been developing various unique and specialized selectional processes for the applicants. In this research, through a statistical analysis of special admission processes for vocational high school students who were admitted to a regional state-run university (University A), I tried to find a way to effectively deal with the student management. Statistically analyzing these first-year students' enrollment and their adjustment processes as well as the departmental relationships and gender differences, I tried to find some better ways to secure good applicants. It is expected that this study will not only be utilized as guide to adopt a way to bypass the enrollment quota in order to secure talented students but also be served as a reference that will help the students adapt themselves to school life until they graduate. It is also expected that this study will be expanded in such a way as to compare it with other models and even develop a new type of college entrance system that would fit future college admission policies.

• Korean Security Journal
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• no.16
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• pp.81-99
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• 2008

Despite its legal, systematic and quantitative growth, Korean private security has not been showing satisfactory level of qualitative growth comparing to quantitative growth as it socially shocked with recent occurrence of the events and accidents. People on demand of security are making use of private security service to offset insufficient supply of security power as, especially, the incendiarism at Sungryemun last February brought out security issues for nationally important facilities and cultural assets, and other cases showed that the police would not cope with the appropriate security services under the current security system for protecting the life and property of people. For the supplementation of security power, the private security service is prevalent, but lots of service providers would not overcome its small business scale, except some large-sized security providers. There are some problem occurred as some providers employed staff who would not have the stuff for performing security service and they even committed illegal actions. Some opinions pointed out that it should come up with measures as they socially lose their credit. Therefore, this research suggests the recognition of the importance and the improvement measures of human resources management as follows. Security Service needs: 1. control of criteria for the employment/recruitment of human resources; 2. inducement of qualitative improvement of security service by ensuring excellent quality of human resources; 3. elevation of morale of organizational members with the operation of efficient promotion system; 4. introduction of professional certification system for the inflow of excellent quality of human resources.

• Korean Journal of Organic Agriculture
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• v.29 no.2
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• pp.209-221
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• 2021

The purpose of this study is to obtain basic data on housing facilities and management of broiler welfare certified farms in Korea. We investigated breeds, flock sizes, stocking density, perches, litter, plumage condition, and other diseases. In addition, we measured temperature, relative humidity, light intensity, ammonia, and carbon dioxide concentration in the barn. As result, criteria were met in all cases that we investigated. However, farmers commonly demanded relaxation of perch and litter. Perch usage of broiler was impractical due to low usage of it. Also, litter was increased, resulting in farmers' economic burden by the imbalance between supply and demand. This situation makes farmers reuse the litter. Unfortunately, there are no clear certification standards. During re-inspection, the animal welfare certification of farms was canceled due to the reuse of litter. It is difficult to modify the standard of perch due to the strong declarative meaning of animal welfare rather than the necessity of perch usage, however, the reuse of litter should be improved. It is important to think and solve any problems faced by all farms. Especially, animal welfare standards need to be improved in more clarity and rationality.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.539-545
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• 2018

In recent years, research on shipping market forecasting with the employment of non-linear AI models has attracted significant interest. In previous studies, input variables were selected with reference to past papers or by relying on the intuitions of the researchers. This paper attempts to address this issue by applying the stepwise regression model and the random forest model to the Cape-size bulk carrier market. The Cape market was selected due to the simplicity of its supply and demand structure. The preliminary selection of the determinants resulted in 16 variables. In the next stage, 8 features from the stepwise regression model and 10 features from the random forest model were screened as important determinants. The chosen variables were used to test both models. Based on the analysis of the models, it was observed that the random forest model outperforms the stepwise regression model. This research is significant because it provides a scientific basis which can be used to find the determinants in shipping market forecasting, and utilize a machine-learning model in the process. The results of this research can be used to enhance the decisions of chartering desks by offering a guideline for market analysis.