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A Study on Estimation of a Beat Spectrum in a FMCW Radar (FMCW 레이다에서의 비트 스펙트럼 추정에 관한 연구)

  • Lee, Jong-Gil
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.12
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    • pp.2511-2517
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    • 2009
  • Recently, a FMCW radar is used for the various purposes in the short range detection and tracking of targets. The main advantages of a FMCWradar are the comparative simplicity of implementation and the low peak power transmission characterizing the very low probability of signal interception. Since it uses the frequency modulated continuous wave for transmission and demodulation, the received beat frequency represents the range and Doppler information of targets. Detection and extraction of useful information from targets are performed in this beat frequency domain. Therefore, the resolution and accuracy in the estimation of a beat spectrum are very important. However, using the conventional FFT estimation method, the high resolution spectrum estimation with a low sidelobe level is not possible if the acquisition time is very short in receiving target echoes. This kind of problems deteriorates the detection performance of adjacent targets having the large magnitude differences in return echoes and also degrades the reliability of the extracted information. Therefore, in this paper, the model parameter estimation methods such as autoregressive and eigenvector spectrum estimation are applied to mitigate these problems. Also, simulation results are compared and analyzed for further improvement.

Urbanization in Pusan City, Korea: Changes of Traffic Volume (교통량 변화로 본 부산의 도시화)

  • Kim, Won-Kyung;Beun, Jeong-Hee
    • Journal of the Korean association of regional geographers
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    • v.4 no.2
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    • pp.1-14
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    • 1998
  • This research concerns with the urbanization in Pusan City, the largest port city of Korea focus on the changes of traffic volume from 1970 to 1994. These results are as follow: (1) Urbanization of Pusan City has progressed with increasing the efficiencies of streets. At the first, it's ribbon developed along the main artery toward inland. Urbanization is the process of bear a resemblance to characteristics of CBD. It has both expansion and diffusion processed, simultaneously. Urbanization has progressed centered certain nuclei and developed with more varieties are ally and temporally. (2) Traffic volumes according to times which go and return to piers affected to the traffic pattern of the some parts within the city, it is one of characteristics in port city. Variation of traffic volumes according to times much greater at the nearer streets the piers and connected street with it than the rest of the areas within the city. Rivers and mountains affecting to the traffic pattern and play roles of diffusion barriers for urbanization. (3) In the mid-1980, regions which locate along the main arteries had reached to as same level of urbanization as central part of the city. And higher ranked central places within Pusan City developed toward pattern of CBD in the past. It suggests that these central places revoluted to the recreation of CBD function in the past. (4) Urbanization has developed as same as cell differentiation in process, and it encouraged the more greater variation among the regions and become clear the hierarchy of central places within the city.

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Long-Period Wave Oscillations in Sokcho Harbor and Cheongcho Lagoon (1. Field Measurements and Data Analyses) (속초항과 청초호의 부진동 특성 (1. 현장관측과 자료 분석))

  • 정원무;박우선;김규한;채장원;김지희
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.14 no.1
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    • pp.51-64
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    • 2002
  • To investigate long-period wave responses in Sokcho Harbor and Cheongcho lagoon, field measurements were made for long-and short-period waves and current velocities using a Directional Waverider, a ultrasonic-type wave gauge, four pressure-type wave gauges, and a current meter. From the data analysis, it was found that the Helmholtz resonant periods of Sokcho Harbor and Cheongcho lagoon are about 13.6 and 54.5 minutes, respectively, and the dominant period of wave induced current in the passage between Sokcho Harbor and Cheongcho lagoon is about 55.2 minutes which depends on Helmholtz resonant condition of the Cheongcho lagoon. It was also found that the energy level of the far-infra-gravity waves during storm conditions is very high compared with that during calm sea conditions. To investigate relationships between far-infra-gravity waves and short-period waves at offshore station, regression analyses were carried out especially for 1) heights, 2) periods, 3) direction and height, 4) height and period between short-and far-infra-gravity waves, respectively. The results showed that the long-period wave height is highly correlated with the short-period wave height. However, no special trend was found for the other relations. In the future far-infra-gravity wave heights on return period around Sokcho Harbor region can be suggested by using extreme value analyses of long term measured data.

Medical Achievements of Doctor-Lee, Seokgan and Interpretation of the first unveiled 「Daeyakbu」 (조선 중기 유의(儒醫) 이석간(李碩幹)의 가계와 의약사적 연구 - 새로 발견된 대약부(大藥賦)를 중심으로 -)

  • Oh, Jun-Ho;Park, Sang-Young;Ahn, Sang-Woo
    • The Journal of Korean Medical History
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    • v.26 no.1
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    • pp.87-96
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    • 2013
  • This study confirmed that a doctor named Lee, Seok-gan whose name has been widely known but whose real identity has remained unclear, was an active Confucian doctor in the 16th century. In addition, through the newly discovered "Daeyakbu" among his family line, writings, and relics that have been handed down in a family, this study looked into his medical philosophy and medicine culture. The author of "Ieseokgangyeongheombang"(Medical Book by Lee, Seok-gan(李石澗), Seok-gan is the same person as an active famous doctor Lee, Seok-gan(李碩幹, 1509-1574) in the 16th century. Such a fact can be confirmed through "Samuiilheombang", "Sauigyeongheombang" and the newly opened "Ieseokgangyeongheombang". Lee, Seok-gan was born in the 4th ruling year of king Jungjong (1509) and was active as a doctor until the 7th ruling year of king Seonjo(1547); his first name is Jungim with the pen name-Chodang, and he used a doctor name of 'Seokgan.' He was known as a divine doctor, and there have been left lots of anecdotes in relation with Lee, Seok-gan. Legend has it that Seokgan went to China to give treatment to the empress, and a heavenly peach pattern drinking cup and a house, which the emperor bestowed on Seokgan in return for his great services, still have remained up to the present. Usually, Seokgan interacted with Toegye Lee Hwang and his literary persons, and with his excellent medical skills, Seokgan once gave treatment to Toegye at the time of his death free of charge. His medical skills have been handed down in his family, and his descendant Lee, Ui-tae(around 1700) compiled a medical book titled "Gyeongheombangwhipyeon(經驗方彙編)". Out of Lee, Seok-gan's keepsakes which were donated to Sosu museums by his descendant family, 4 sorts of 'Gwabu'(writings of fruit trees) including "Daeyakbu" were discovered. It's rare to find a literary work left by a medical figure like this, so these discoveries have a deep meaning even from a medicine culture level. Particularly, "Daeyakbu" includes the typical "Uigukron". The "Uigukron", which develops its story by contrasting politics with medicine, has a unique writing style as one of the representative explanatory methods of scholars' position during the Joseon Dynasty; in addition, the distinctive feature of "Uigukron" is that it was created in the form of 'Gabu' other than a prose.

Seniority Based Pay System and the Relational basis of Workplace Inequality (연공성임금을 매개로 한 조직내 관계적 불평등: 내부자-외부자 격차에 대한 분석)

  • Kwon, Hyunji;Ham, Sunyu
    • Korean Journal of Labor Studies
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    • v.23 no.2
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    • pp.1-45
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    • 2017
  • This study aims at explaining organizational mechanisms of inequality that has been rising rapidly alongside the proliferation of irregular employment in the post-crisis Korean labor market. It argues that inequality is not sufficiently explained by individual gap in human capital or widespread marketization as such. Social categories into which each individual worker falls seems more important as a source of labor market inequality. Employment types that are composed of regular and irregular employment do not simply indicate the different economic meanings of employment contracts but have rather been institutionalized as a social category of status in the context of inequality over the past two decades. They are also often matched with other social categories such as gender that have created and reproduced greater labor market inequality. We pay attention to the organizational practice of dominant incumbents who make claims for advantages of return based on their exclusive accessibility to limited organizational resources and explain how that particular practice plays a role to increase relational inequality between those insiders who achieve advantageous returns and outsiders mostly irregular workers who are excluded from those resources because of the social categories that they belong to. In this study, we identify seniority based pay as the key organizational practice that justifies categorical differences within the workplace and examine how that particular practice contributes to organizational level segmentation and income ineqaulity.

Comparison of 'Militarism' and 'Normal state' through the Concept of Regional Hegemony: Focus on Imperial Japan before and after the Navy Disarmament Treaty and Modern Japan after Abe Shinzo's 2nd Cabinet (지역 패권 개념을 통한 '군국주의'와 '보통국가' 비교: 해군 군축조약 전·후 일본제국과 아베 2기 내각 이후 현대 일본의 사례를 중심으로)

  • Kim, Dong-eun
    • Maritime Security
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    • v.1 no.1
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    • pp.1-30
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    • 2020
  • The study started with the question, "Is Japan's normalization of nationalization a return to militarism?" Therefore, in order to analyze this, the characteristics of the international system after the inauguration of the Japanese Empire during World War I and World War II and the Abe's 2nd Cabinet in contemporary Japan were compared. Through this, there were some differences in the characteristics of the international system of the two periods, and as a result, it was intended to derive the differences between the two examples. During the prewar period of World War I, the militaristic Japanese Empire suffered great damage from the national pride of being the only power in Asia through the Paris Enhancement Conference, the Washington Navy Treaty, and the London Navy Treaty. However, the Western powers with colonies in Asia still existed in the region, so it was not possible to turn them into immediate power expansion. Meanwhile, World War II broke out in Europe. As a result, the Western powers had to focus on the whole of Europe, and the militaristic Japanese empire became a regional hegemony without missing the international system characteristic of "the hegemony." Unlike in the past militarism, Japan's case of pursuing common nationalization since 2012 has been carried out in the order of Northeast Asia in the composition of the "cold war" new cold war. In particular, Japan is attempting to transform itself into a normal state to strengthen the US-Japan alliance on a self-reliant level due to the lack of quantitative military power compared to the neighboring countries.

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A Study on Factors on Postpartum Obesity and Postpartum Depression in Korea (국내 산후 비만과 산후 우울증 관련 요인 연구)

  • Ku, Jung-Eun;Kim, Gyu-Ri
    • Journal of Digital Convergence
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    • v.19 no.6
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    • pp.429-438
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    • 2021
  • This study aims to prevent maternal social isolation by analyzing the causes of postpartum obesity and postpartum depression and stress in Korea. Gneral characteristics of mothers as a result of the study: 91.1% (102 people) answered that they had social experience, and only 8% (9 people) answered that they had no social experience. In the question of whether to return to society, 17.9% responded that they have already returned, 54.5% did not, and 18.8% were on maternity leave. As a result of examining the level of BMI increase among mothers through chi-square test of BMI changes before and after childbirth and general characteristics, 55% experienced below-average BMI increase; 45% experienced above-average BMI increase. Those in their 30s accounted for 40.2%, and those in their 40s accounted for 57.1%. Postpartum obesity and maternal psychological status (t-test): Mothers with postpartum obesity were more hypersensitive (t = -1.997, p = 0.048) and more prone to suffer from hard breathing (t = -1.930, p = 0.056), emptiness (t = -2.673, p = 0.010), and body numbness (t = -2.315, p = 0.024) than mothers who are not suffering from not postpartum obesity. Per the results of postpartum BMI increase and maternal psychological state (t-test) analysis, mothers with an average increase in postpartum BMI were more depressed than mothers who did not. Research Results - Postpartum obesity due to pregnancy and childbirth has been identified as an important individual cause affecting mental and physical problems after childbirth. In conclusion, I also think that the government should support the management of maternal obesity and the elimination of depression through the results of this study.

Relationship Between Work Ability, Self-efficacy, Work Satisfaction, Sequelae and Workplace Relationships of Reemployed Workers Who Experienced Industrial Accidents (재취업한 산재 노동자의 업무능력, 자기효능감, 직무 만족, 후유증, 동료관계의 구조적 관계)

  • Kim, Do-Hee
    • Journal of Digital Convergence
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    • v.20 no.2
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    • pp.463-477
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    • 2022
  • The current study examined the mediating effect of self-efficacy (SE) in the relationship between work ability (WA) and work satisfaction (WS) perceived by reemployed workers who have experienced industrial accidents based on social cognitive career theory (SCCT), and investigated the effect of Industrial accident sequelae and workplace relationships (WR) on these variables. The data of 976 newly employed workers were selected from the data of the Panel Study of Worker's Compensation Insurance collected in 2018. The data were analyzed by Structural Equation Modeling through SPSS and AMOS programs. It was found that WA had a positive effect on WS through SE. In addition, it was found that the level of pain, the severity of the disability, and the activities of daily living had a negative effect on WS through WA and SE sequentially. Meanwhile, it was found that the WR was affected by the activities of daily living, and had a positive effect on WS through WE. These results emphasize that it is important to provide support to manage sequelae and increase SE in order to help victims of industrial accidents return to the job market and live satisfactorily. It also suggests that SCCT is useful in explaining WS of industrially injured workers.

An Analysis of Economic Evaluation and Spread Effects on the Establishment of Public Sports Facilities (공공스포츠시설 건립의 경제성 평가 및 파급효과 분석)

  • Kim, Jin-Kook;Jang, Won-Yong;Choi, Kyoung-Ho
    • Journal of Korea Entertainment Industry Association
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    • v.13 no.1
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    • pp.111-119
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    • 2019
  • The purpose of study was to evaluate the economic evaluation of Chuncheon curling stadium. In oder to estimate economic evaluation, benefit/cost ratio, net present value and internal rate of return were used. Additionally, in order to investigate the socio-economic spread effect, literature review and input-output analysis were used. The results of study were as follows. First, as a result of analyzing the demand for curling stadiums in Chuncheon, it was believed that the construction of the stadium will attract athletes from the Chuncheon region as well as athletes from Seoul, Incheon, Gyeonggi Province and North Chungcheong Province. Second, economic validity analysis showed that the initial investment did not make sense, but the players' training and competitions and the advantages of the potential experience of curling events for citizens in nearby areas, including Chuncheon, make the construction and operation reasonable. Third, as a result of the review of the social and policy validity of the curling stadium, the project to build a curling stadium in Chuncheon was secured with a policy validity as a public sports facility necessary for both professional and living athletes. Finally, the analysis of socio-economic spread effect of curling stadiums had shown that it would have a positive effect on the level of satisfaction of the general public as well as the discovery of elite athletes.

Varietal Differences on Growth Characteristics of Direct-sown Rice under No-tillage Paddy Field (남부지방의 벼 무경운 직파재배에서 품종간 생육특성 비교)

  • Hong, Kwang-Pyo;Kim, Jang-Yong;Kang, Dong-Ju;Shin, Won-Kyo;Choe, Zhin-Ryong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.41 no.5
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    • pp.551-557
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    • 1996
  • In order to establish a labour-saved and environment friendly paddy rice system in southern Korea, no-tillage paddy system was proposed and investigated from 1992 to 1993. Basically this system includes a complete return of crop residules into the soil, and zero-tillage. In an effort to minimize labour requirement in rice farming, several cultivars were directly sown and grown under the system and the characteristics of the growth and yield potential of the cultivars were compared with those grown in an ordinary paddy soil. Joryeongbyeo, Dongjinbyeo, Daeyabyeo and Calose rices showed high level of seedling establishment in the no-tillage padddy system. However, the value was significantly lower than in those of the cultivars direct-sown in an ordinary tillage paddy condition. The rice direct-sown and grown under the no-tillage paddy system showed significantly decreased number of tillers per square meter and plant height, but increased ripened grains. The lodging-related characteristics of rice plant, such as band breaking weight, the length of top 3rd ∼4th internodes, the height of weight center, and lodging index, were observed positive aspects in cultivars such as Hwasungbyeo, Hwayongbyeo, Joryeongbyeo, Calose and Calose 76 and being considered adaptable to direct-sown under the no-tillage paddy system.

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