• Korean Journal of Remote Sensing
• /
• v.24 no.2
• /
• pp.91-98
• /
• 2008

We present an efficient and robust technique to estimate the velocity of moving targets from a single SAR image. In SAR images, azimuth image shift is a well blown phenomenon, which is observed in moving targets having slant-range velocity. Most methods estimated the velocity of moving targets from the distance difference between the road and moving targets or between ship and the ship wake. However, the methods could not be always applied to moving targets because it is difficult to find the road and the ship wake. We propose a method for estimating the velocity of moving targets from azimuth differentials of range-compressed image. This method is based on a phenomenon that Doppler center frequency shift of moving target causes a phase difference in azimuth differential values. The phase difference is linearly distorted by Doppler rate due to the geometry of SAR image. The linear distortion is eliminated from phase removal procedure, and then the constant phase difference is estimated. Finally, range velocity estimates for moving targets are retrieved from the constant phase difference. This technique was tested using an ENVISAT ASAR image in which several unknown ships are presented. In the case of a isolated target, the result was nearly coincident with the result from conventional method. However, in the case of a target which is located near non-target material, the difference of the result between from our algorithm and from conventional method was more than 1m/s.

• Korea journal of population studies
• /
• v.11 no.1
• /
• pp.197-203
• /
• 1988

In order to examine cause-specific mortality in Korea by comparing mortality of Japan, various mortality indicators are calculated using 1995 of ficial statistics of twonations. The mortality measures are cause-specific mortality rate by sex, age, andmarital status, cause-specific age-standardized death rate and potential years of lifelost, and their ratios by sex and nation. Items of major causes of death include allcauses (total deaths),tuberculosis, malignant neoplasm, diabetes mellitushypertensive diseases, heart diseases, cerebrovascular diseases, liver diseasestransport accidents, and suicide. Major characteristics of mortality in Korea are asfollows . (1) Death rates from most causes except suicide are higher in Korea thanJapan and especially death rates from tuberculosis, hypertensive diseases, liverdiseases, and transport accidents are higher for economically active Koreans : (2)Death rates from tuberculosis, liver diseases, transport accidents, and malignantneoplasm are salient for Korean children (3) Sex-differentials in mortality fromliver diseases, tuberculosis , and transport accidents are large for economically activeKoreans, because male mortality is higher than female mortality : (4) Suicide ratesare lower for economically active males, and higher for females aged 10s and 20s inKorea than Japan : (5) Death rates are highest f3r divorced or widowed under 45years of age depending on causes, but death rates from all causes are highest fornever-married of the age 45 and over in Korea : and (6) Sex-differentials inmortality are greatest for widowed in Korea and for divorced in Japan.

• Journal of Energy Engineering
• /
• v.25 no.1
• /
• pp.9-14
• /
• 2016

This study has been carried out to develop TM (Thermal to Mechanical) conversion systems for electric power generation using one of the Low Temperature Differential (LTD) Stirling engines called MM-7 capable of harnessing low temperature waste heat whose temperature is only $20{\sim}30^{\circ}C$ above the ambient. Measurements were made on the torque and rpm for a number of temperature differentials between the engine hot and cold ends, which could be effectively applied in developing the most suitable configuration for the high performance TM (Thermal to Mechanical) conversion system.

• Asian Journal of Innovation and Policy
• /
• v.4 no.1
• /
• pp.1-18
• /
• 2015

Most research on Official Development Assistance (ODA) targeted the recipients, but this study examines the effect of ODA on the donor's exports to the recipient. To do this, a panel analysis was carried out with ODA and macroeconomic data on the United States and 33 other countries from 1999 to 2009. The results are summarized as follows: (1) The economic influence on the donor varies with the recipient's localization effort. (2) High-tech exports to the recipient are independent of ODA. (3) In medium-to-low-technology areas, ODA has a positive effect on exports to the recipient with low absorption efforts. (4) Both High-tech and LM-tech product exports decreases with the technological innovation efforts of recipients with high absorption efforts, while High-tech product exports only increases with that of recipients with low absorption efforts. These results indicate that a strategic approach for ODA program is more effective and useful to the donor's economy.

• Spatial Information Research
• /
• v.8 no.2
• /
• pp.289-300
• /
• 2000

The development of a UIS driven by muncipal governments has been expanding through the wide application of GIS since NGIS project initiated. City of Inchon has developed a sewage management system as the first-year product of the long-term UIS project. GIS auditing process has been adopted to secure the credibility and stability, and to minimize the critical failure factors for building the sewage management system. So far, the auditing method generally used for developing information system in general purposes has been applied to the GIS field due to the absence of proper method for GIS auditing only. This study proposes major differentials in terms of the auditing between GIS and general information system based on the results from auditing Inchon´s sewage management system. The major results from this study would contribute to the establishment of the methodology and accompanying documents for the proper GIS auditing.

• Korean journal of applied entomology
• /
• v.22 no.3 s.56
• /
• pp.208-212
• /
• 1983

Sixteen recommended soybean cultivars in Korea were tested for resistance to Heterodera glycines. The nubmer of females which developed on roots of cultivars were fewer on 'Hwanggeum kong' and greater on 'Geumgangdaelib'. But there was no resistant cultivar to Heterodera glycines. Four field populations of Heterodera glycines tested for ability to reproduce on five host differentials. Geographical differentiations of H. glycines were newly founded in Korea. These were identlified to race 1 at Hwasun, race 5 at Yangsan and Suweon and Unknown race(or race C) at Seonsan.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1705-1709
• /
• 2005

The hydraulic LSD which uses the principle of gear pump is packed with viscous oil in tight container. When a slip occurs on one wheel, the hydraulic LSD generates torque caused by high oil pressure in the container. In this study, two dimensional(2-D) side pinion gear model was developed for hydraulic LSD. Using that model the flow analysis was conducted to preestimate pressure distributions of the side pinion gear according to the variations in the design factors such as oil viscosity, gear gap and rpm. Then, applying the obtained pressure distributions on the side pinion gear, finite element analysis was conducted to evaluate the torque characteristics. From the analysis results, the torque characteristics according to the design factor variations were evaluated.

• Journal of Labour Economics
• /
• v.37 no.4
• /
• pp.113-141
• /
• 2014

This paper examines the occupational gender wage gap in the Korea labor market. This paper classifies occupations into three(the blue-collar profession, white-collar profession and female-dominated profession) according to job characteristics and female worker's ratio. To analyze occupational gender wage gap, this paper uses Mincer's wage equation(1974) and Oaxaca model(1973). The results are listed below. First, the gender wage gap is growing in all occupations. Second, the cause of increasing gender wage gap varies in different occupations.

• Human Ecology Research
• /
• v.58 no.3
• /
• pp.343-356
• /
• 2020

This paper examines the associations of having a helper for domestic work or childcare and time spent on it by couples in South Korea. We use five waves of panel survey data from the Korean Longitudinal Survey of Women and Families (KLoWF), which allows longitudinal changes within couples over time that account for potential selection effects and unobserved heterogeneity among individuals. With fixed effects, we find outsourcing is associated with a decrease in wife's time spent on domestic work or childcare by 1 hour per week. However, the decrease is concentrated on the unemployed wife's time, but not employed wife's time. In addition, outsourcing is not a significant factor for husband's time and the husband's share of total contribution. This may be because wives are the main provider of domestic work and childcare in Korea regardless of employment status or having any helper. Due to unequal contributions between husband and wife, using outsourcing also neither alleviates the employed wife's contribution nor changes the husband's contribution. However, the results may be underestimated because there are more common and diverse types of outsourcing in a broad sense, such as going out for dinner, buying prepared food, and using dry cleaning services. We expect future studies to consider more broad types of outsourcing and examine how relations with the couple's time use at home are different by type.

• Fire Science and Engineering
• /
• v.20 no.1 s.61
• /
• pp.77-82
• /
• 2006

This study defined engineering mechanism and compensation method to establish reference pressure of smoke control zone with atmospheric pressure that is compensated for temperature. The reliable controller of integration smoke control was developed by establishing the specifications, algorithms and constructing engineering data. The development of controller for integration smoke control can cut down number of processes, manufacturing and installation cost by removing pressure measurement pipe established separately for non smoke control zone, and improve the accuracy of pressure differential by embedding pressure measurement ports for non smoke control zone. More correct and reliable pressure differentials can be obtained by the central control from controller of integration smoke control rather than the existent individual control. This will provide the basics and the flexibility to the integral smoke control system and accordingly improve the performance of disaster prevention.