• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.862-877
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• 2008

In this paper, two types of wideband 3-dB ring hybrids are compared and discussed to show the ring hybrid with a set of coupled-line sections better. However, the better one still has a realization problem that perfect matching can be achieved only with -3 dB coupling power. To solve the problem, a set of coupled-line sections with two shorts is synthesized using one- and two-port equivalent circuits and design equations are derived to have perfect matching, regardless of the coupling power. Based on the design equations, a modified ${\Pi}-type$ of transmission-line equivalent circuit is newly suggested. It consists of coupled-line sections with two shorts and two open stubs and can be used to reduce a transmission-line section, especially when its electrical length is greater than ${\pi}$. Therefore, the $3\;{\lambda}/4$ transmission-line section of a conventional ring hybrid can be reduced to less than ${\pi}/2$. To verify the modified ${\Pi}-type$ of transmission- line equivalent circuit, two kinds of simulations are carried out; one is fixing the electrical length of the coupled-line sections and the other fixing its coupling coefficient. The simulation results show that the bandwidths of resulting small transmission lines are strongly dependent on the coupling power. Using modified and conventional ${\Pi}-types$ of transmission-line equivalent circuits, a small ring hybrid is built and named a compact wideband coupled-line ring hybrid, due to the fact that a set of coupled-line sections is included. One of compact ring hybrids is compared with a conventional ring hybrid and the compared results demonstrate that the bandwidth of a proposed compact ring hybrid is much wider, in spite of being more than three times smaller in size. To test the compact ring hybrids, a microstrip compact ring hybrid, whose total transmission-line length is $220^{\circ}$, is fabricated and measured. The measured power divisions($S_{21}$, $S_{41}$, $S_{23}$ and $S_{43}$) are -2.78 dB, -3.34 dB, -2.8 dB and -3.2 dB, respectively at a design center frequency of 2 GHz, matching and isolation less than -20 dB in more than 20 % fractional bandwidth.

• Journal of electromagnetic engineering and science
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• v.9 no.2
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• pp.85-97
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• 2009

As operating frequency is raised and as more integration with active and passive elements is required, it becomes difficult to fabricate more than 120 ${\Omega}$ characteristic impedance of a mierostrip line. To solve this problem, an equivalent high impedance transmission-line section is suggested, which consists mainly of a pair of coupled-line sections with two shorts. However, it becomes a transmission-line section only when its electrical length is fixed and its coupling power is more than half. To have transmission-line characteristics(perfect matching), independently of coupling power and electrical length, two identical open stubs are added and conventional design equations of evenand odd-mode impedances are modified, based on the fact that the modified design equations have the linear combinations of conventional ones. The high impedance transmission-line section is a passive component and therefore should be perfectly matched, at least at a design center frequency. For this, two different solutions are derived for the added open stub and two types of high impedance transmission-line sections with 160 ${\Omega}$ characteristic impedance are simulated as the electrical lengths of the coupled-line sections are varied. The simulation results show that the determination of the available bandwidth location depends on which solution is chosen. As an application, branch-line hybrids with very weak coupling power are investigated, depending on where an isolated port is located, and two types of branch-line hybrids are derived for each case. To verify the derived branch-line hybrids, a microstrip branch-line hybrid with -15 dB coupling power, composed of two 90$^{\circ}$ and two 270$^{\circ}$ transmission-line sections, is fabricated on a substrate of ${\varepsilon}_r$= 3.4 and h=0.76 mm and measured. In this case, 276.7 ${\Omega}$ characteristic impedance is fabricated using the suggested high impedance transmission-line sections. The measured coupling power is -14.5 dB, isolation and matching is almost perfect at a design center frequency of 2 GHz, showing good agreement with the prediction.

• Therapeutic Science for Rehabilitation
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• v.13 no.1
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• pp.87-97
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• 2024

Objective : This study aimed to acquire activities of daily living (ADL) skills through activity analysis and forward chaining in children with developmental disabilities. Methods : In this study, the performance of children with developmental disabilities was guided stepwise using a changing criterion design. The intervention was conducted in forward chaining after the therapist analyzed the activities of three tasks (shoes, shorts, and short-sleeved T-shirts) set as the Canadian Occupational Performance Measure (COPM). The performance rate at each stage of the three tasks was used as an independent variable, and COPM performance and satisfaction scores before and after the intervention were set as dependent variables. Results : The task performance rates of children wearing shoes, shorts, and short-sleeved T-shirts improved over time. Even at home, the scores for performance and satisfaction of all three tasks increased. Conclusion : Hopefully, activity analysis and behavioral chaining methods will be used not only for ADL but also for various tasks in children with developmental disabilities who have difficulty acquiring tasks.

• Journal of the Korea Fashion and Costume Design Association
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• v.6 no.2
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• pp.89-102
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• 2004

Modern society is age of sports just as health and leisure became dominant concern, which has caused the fixation and development to sports wear considered as fashion for everyday dress. This paper focused on the development process and aesthetic characteristics of knit design expressed in the 20th century sports wear. The importance and direction of knit design in modern sports wear is expected. Style, items, fabrics, colors, details and top designers were analyzed in sports wear from the 1910' s to 1990' s. Sports wear can be categorized into two of the active sports wear and spectator sports wear. Since disappearance of division between ordinary wear and sports fashion in the 1970' s, the functional wear of leggings, cycle shorts, exercise clothes, leotard, and leg warmer appeared. Vicennial developments of synthetic fibers and new fabrics have caused the great changes in knit design. Colors were vivid in the 1950' s, metallic in the 1970' s and neon in the 1990' s. Sportive sense was expressed by various details. The dominant knit designers who expressed aesthetic characteristics to sports wear were Coco Chanel, Claire McCardell, Balenciaga, Andre Courrege, Pierre Cardin, Yves Saint-Laurent, Ralph Lauren, Donna Karan, and Giogio Armani.

• Journal of the Korea Fashion and Costume Design Association
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• v.22 no.2
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• pp.151-165
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• 2020

In this study, the pattern of texture was developed by applying the pattern shown in the Amita Yeoraebul and the Avalokitesvara with symbolism suitable for children's clothing. In addition, the design and the manufacturing of a children's wearable Hanbok were attempted, and the results are as follows: Amitha Yeoraebul is a Buddha who oversees paradise in Buddhism, and Avalokitesvara controls both paradise and the real world and provides mercy. Applying the various patterns in the Buddhist paintings, four daily hanboks for children were produced using patterns featuring symbolic the meanings of large round original patterns chrysanthemums, turtles, and lotus patterns. The lotus symbol represents love, nobility, and wealth, while the turtle symbol represents longevity, the chrysanthemum pattern symbolizes auspiciousness, and the large round original pattern means a constant continuation. To maintain the traditional hanbok form but allow convenient wear it in daily life, it is made in the jeogori + shorts, vest + long pants, and one-piece + jacket style. Currently, the daily dress of Hanbok and the modernization of traditional Korean clothes are being promoted. At this point, the study developed Hanbok fashion products that contain symbolic stories suitable for children are trying to maintain the image of traditional culture as much as possible.

• Journal of Korean Biological Nursing Science
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• v.13 no.3
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• pp.269-275
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• 2011

Purpose: This study was designed to help preparing the evidence-based data for the manual of heat applications by finding the differences of superficial and core temperatures after applying dry and moist heats on shoulder and thigh. Methods: Moist and dry heats were alternately applied on the 33 subjects a day apart from May 15, 2010 through June 9, 2010. The experiment was conducted with $23^{\circ}C$ to $25^{\circ}C$ room temperature and 50% to 66% of moisture from 2 to 6 p.m. After heat was applied on the shoulder of the subjects wearing shorts and gowns for 30 minutes, their superficial and core temperatures were measured. The same method was used on the thigh after two hours. Results: Both superficial and core temperatures on the shoulder and thigh increased significantly after heat therapy. There was no significant difference between the temperatures before and after intervention according to applying methods and regions. Conclusion: This study provides a theoretical basis that a dry heat is a convenient nursing intervention for hypothermic patients.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2123-2135
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• 1997

In this paepr, we consider resistive shorts on drain-source, drain-gate, and gate-source as well as opens in MOSFETs included in typical memory cell of VLSI SRAM. Behavior of memeory is observed by analyzing voltage at storage nodes of memeory and IDDQ(quiescent power supply current) through PSPICE simulation. Using this behavioral analysis, an effective testing algorithm of complexity O(N) which can be applied to both functional testing and IDDQ testing simultaeously is proposed. Built-In Self Test(BIST) circuit which detects faults in memories and Built-In Current Sensor(BICS) which monitors the power supply bus for abnormalities in quescent current are developed and imprlemented to improve the quality and efficiency of testing. Implemented BIST and BICS circuits can detect locations of faults and defects in order to repair faulty memories.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.155-159
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• 2016

In this work, we have developed a test system to examine whether the charge indicator of the plug-in hybrid electric vehicle (PHEV) works properly or not. In PHEV, the driver should charge the necessary electricity by plugging in manually and be able to know the charging status through the charge indicator conveniently located for the charging individual. Our system used the CAN bus to transmit the same commands from ECU to the indicator to test the proper operation of the indicator lights. It measured the electric current values during operation and analyzed to determine the quality of the indicators. The inspection items included the proper packaging, the electrical shorts, the LED lighting during charging, the LED lighting for charging failure, and the LED lighting when errors occur. We developed the system for the operators in the factory allowing them to approve the test results at the site. We developed the hardware, the control software, and the software to store the test results and the history of the products in the database. Serial numbers were given to the good quality products and the bar code labels were printed to trace the products afterwards. Through this work, we developed a system to inspect the electric parts in real time upon fabrication. We are planning to further improve our system to inspect the brightness of the indicator by adding the vision inspection in future.

• The Journal of the Korea Contents Association
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• v.2 no.4
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• pp.67-75
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• 2002

As the knowledge-based society progresses the amount of information increases tremendously and also the accessibility to information is much improved through the diffusion of internet and digitalized contents. At this juncture the systematic management and efficient analysis of immense information surfaces as a global issue. And the paradigm of information turns from the age of information access to the age of information analysis. So it is urgently required to analyze technology trend from technology information and to establish the way to realize a systematic method for information analysis. Accordingly in this study an information analysis system is developed that contributes to the decision of proper direction for R&D and technology development by rapidly and systematically analyzing search results from the technology databases online and can reduce to a great degree the shorts and time required to collect and analyze information.

• Journal of the Korean Society of Costume
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• v.11
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• pp.31-43
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• 1987

The present research is to study a variation of skirt length in the time series, from 1955 to 1986. The results are summarized as follows; 1. The most important event is the acceptance of Mini skirts during this period. This phenomenon will play an important role in later skirt length. 2. The year of the shortest skirt length is 1972, while the year of the longest skirt length is 1983. 3. Based upon the year of the shortest skirt length, the periods of the same skirt length are as follows; 1956-1975. 1964-1978. 1959, 1960-1980, 1981. 1961-1982. This phenomenon is irregularly appeared in this study, but shows the change of recurring skirt length. 4. The skirt length has been changed slowly and continuously during the long period of time. In particular, to reach the shortest skirt length takes longer time than that of the longest skirt length. 5. It has taken 6-8 years to reach the top period of Mini skirts (1971-1973) since shorts are introduced. Comparing this phenomenon in Korea with that in Japan, the time difference is about two years. 6. The periods of various skirts length are the year of 1970-1971 and the year of 1972-1973; This result is assumed that individual persons accept sooner or later the changed skirt length. 7. It is belived that Mini skirts are appeared and popularized by external factors. Once Mini skirts are accepted, we can expect that they will be continuosly changed in the course of recurring skirt length.