• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2280-2288
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• 2014

The conventional dimming control methods of LED (Light-emitting dioades) include Analog, PWM (Pulse Width Modulation), and FM (Frequency Modulation) Control. Analog dimming is controlled by adjusting forward current of Power LED. Although Analog dimming is possible to control linearly the brightness levels on a whole range (0%~100%), it comes into existence a variation of wavelength by changing the Power LED's forward current. PWM dimming has achieved by varying in duty of full current flowing to the Power LED. Generally, PWM dimming doesn't make variation of wavelength but have difficulty with adjusting the linear brightness level between 0% and 10%. FM dimming method is on the same wavelength as PWM dimming, however, it has problem of flickering at low level of dimming. This paper propose a efficient dimming control method of Power LED in order to overcome the disadvantages of the above mentioned methods. We apply to Analog method in low level of dimming control and use PWM method in dimming range from 10% to 100%. For the experiment, we design and implement a circuit and test the proposed method. Consequently, we can control the linear brightness of Power LED across the whole range and get the constant wave at different dimming level. The experimental results show the benefits of the proposed method.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.905-915
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• 2010

With rising food waste, the management activities have gained growing attention, and the disposal options, particularly utilization of food waste for energy recovery, become central. This research examines the factors affecting food waste generation and the tendency to resource food waste. The self-administered questionnaire survey was conducted in newly built multifamily housing estates to collect data, and 300 responses were analyzed. The statistical analysis showed that most of the respondents purchased food materials in largely franchised grocery stores and discarded food that had been too long refrigerated to edible. The lifecycle of food consumption was divided into three states - food purchase plan, cooking and food waste collection. Regression analysis was employed to find out the relationships between three stages and food waste generation or tendency to resource food waste. The results described that food waste generation being affected by the stage of food purchase plan (food waste removal conditions) was statistically significant while it's statistically significant that the stage of cooking (prepurchase considerations) influenced the attitude toward food waste resource. The research findings indicated that food is overconsumed, and further many viewed food waste resources as a proactive and integrative mode in the global wave of sustainability.

• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.37-43
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• 2014

Natural disasters such as earthquakes and tsunamis occur suddenly, so that they cause massive loss of lives and property. Especially earthquakes represent a particularly severe threat because of the extensive damage accompanied by them. In Korea, an earthquake-resistant design has been rarely applied to a design or construction of slope. However, in resent years, the researches for earthquake-resistance have been performed because the importance on the earthquake-resistance is perceived and highlighted. Soil nail method, one of the slope stability methods, is excellent for its constructability and cost effectiveness, as compared with other stability methods. Also, this method has been widely used for reinforced construction for slope stability. The studies of soil nail method have been performed on the interaction behavior between nails and slopes as well as the varied load condition such as static load, dynamic load and so on. Nevertheless, there has been minimal research regarding the constraint condition of nail head. In this study, the numerical analysis was performed for identifying effect on slope stability for the constrain condition of the soil nail. The result shows that the resistance of constrained the nail head on reinforced slope is larger compared to the one of unconstrained nail head.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.815-821
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• 2021

This study addresses on the design of performance monitoring system for the time synchronization service of the enhanced long-range navigation (eLoran) system, which has a representative ground-wave radio broadcast system capable of providing positioning, navigation, timing and data (PNT&D) services. The limitations of time-synchronized systems due to the signal vulnerabilities of the global navigation satellite system (GNSS) are explained, and the performance monitoring system for the eLoran timing service as a backup to the GNSS is proposed. The time synchronization service using eLoran system as well as system configurations and the user requirements in the differential Loran (dLoran) system are described to monitor the time synchronization performance. The results of the designed system are presented for long-term operation in the eLoran testbed environment. As the results of time performance monitoring, we were able to verify the time synchronization precision within 43.71 ns without corrections, 22.52 ns with corrections. Based on these results, the eLoran system can be utilized as a precise time synchronization source for GPS timing backup.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.676-687
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• 2021

The main purpose of this study is to study the effect of a program to improve self-esteem and positive thinking in middle-aged women using Buddha Ball meditation. In order to achieve this research purpose, the subject of this study was middle-aged female Buddhists at Temple H in Busan who were interested in 'Buddha Ball'. For the analysis method, empirical analysis was performed using the One Group Pretest-Posttest Design of this study. The main research results are as follows. First, as a result of examining the effect of Buddha Ball meditation on the quality of life, it could be seen that the overall quality of life had a significant positive (+) effect on the experimental group. Second, as a result of examining the effect of Buddha Ball meditation on self-esteem, it could be seen that self-esteem had a significant positive (+) effect on the experimental group. Third, as a result of examining the effect of Buddha Ball meditation on positive thinking, it could be seen that the entire positive thinking had a significant positive (+) effect on the experimental group. Based on these research results, the main conclusion was that the Buddha Ball, a healing meditation tool using the sound wave energy, had a positive effect on the self-esteem and quality of life of middle-aged women Buddhists. Accordingly, it is judged that the Buddha Ball meditation program has a positive use value for middle-aged women who are experiencing more complex psychological difficulties due to individual, family, and social environmental conditions. In addition, by preparing a system that can actively utilize the Buddha Ball meditation program educationally and politically, the implications of the justification and necessity of using it to improve the self-esteem, positive thinking and quality of life of middle-aged women were presented.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.77-84
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• 2022

A submarine power cable is a transmission cable for carrying electric power below the surface of the water. Recently, submarine cables transfer power from offshore renewable energy schemes to shore, e.g. wind, wave and tidal systems, and these cables are either buried in the seabed or lie on the ocean floor, depending on their location. Since these power cables are used in the extreme environments, they are made to withstand in harsh conditions and temperatures, and strong currents. However, undersea conditions are severe enough to cause all sorts of damage to offshore cables, these conditions result in cable faults that disrupt power transmission. In this paper, we explore the design criteria for such cables and the procedures and challenges of installation, and cable transfer splicing system. The specification of submarine cable designed with 3 circuits of 154kV which is composed of the existing single circuit and new double circuits, and power capacity of 100MVA per cable line. The determination of new submarine cable burial depth and cable arrangement method with both existing and new cables are studied. We have calculated the permission values of cable power capacity for underground route, the values show the over 100MW per cable line.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.127-134
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• 2021

When constructing a tunnel on a stable ground, stress is changed in the ground during excavation stage and installation of ground support materials. In the standards for safety evaluation of structures in use, it is suggested to perform numerical analysis reflecting the excavation stage. But method of seismic performance evaluation was not presented. Therefore, in this study, numerical analysis was performed with different analysis methods, and the results were compared and analyzed. As a result of the numerical analysis, seismic wave applied in the horizontal direction were no difference depending on the analysis methods. However, there was a big difference in the result according to the evaluation methods of tunnel member forces. When reviewing with the strength design method, the structure performance could be not satisfied depending on the existence or nonexistence of reinforcing bars. Based on these research results, it is suggested that the interpretation method should be clearly presented and reflected in the relevant standards.

• Asia Marketing Journal
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• v.15 no.1
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• pp.57-81
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• 2013

The purpose of this paper is to seek ways to improve the competitiveness of Korea's fashion industry by utilizing the source of competitiveness of Japan's fashion industry, which represents the world's leading countries in terms of fashion, so that Korea can better enter the global fashion market. The study shall first compare the competitiveness of the Japanese and Korean fashion industries by utilizing the generalized double diamond model; second, provide an understanding of what the Japanese fashion industry can offer to Korean fashion industry and companies - that is, understand what the Japanese fashion industry's competitive edge is; and third, study the kind of global competitiveness that Korea's fashion industry must achieve. To adopt a generalized double diamond model to compare the competitiveness of the Korean and Japanese fashion industries, we selected 31 sub-variables to act as determinants of the model. That is, we extracted 31sub-variables by doing research of literature to analyze national competitiveness of the fashion industries. To measure these 31 sub-variables, secondary data was gathered. We collected data related to each sub-variable from various sources of Korea and Japan. And to calculate the competitiveness index, we took three steps with reference to previous studies. We found that status of the fashion industry of the two countries as it stands. That is, Japan is an advanced country of which fashion industry is domestic market-oriented while Korea is a small open economy that mainly focuses on the foreign market. Out of 31 proxy variables, Korea's fashion industry shows higher measurements relating to production and export than Japan, but Japan's fashion industry reports higher measurements than Korea in the fields of R&D, design and brand power, the rate of value added, the efficiency of companies and globalization. In order for Korea's fashion industry to achieve competitiveness in the global market, it should pursue the following development direction. First, it is very difficult for Korea to follow the footsteps of the U.S. and Japanese fashion industries that are able to take advantage of economies of scale, because Korea is smaller than those countries. Therefore, in the case of small economies such as Singapore, strengthening of international activities will practically improve domestic determinants that Korea should improve its domestic diamond by enhancing the current competitiveness of its international diamond. In other words, Korea needs to further endeavor to develop and expand global resources and markets as well as improve its competitiveness in terms of R&D, design and brand power, the rate of value-added, and the efficiency of companies. As the Korean fashion industry shows relatively advanced level of information technology and the fashion education system, it has considerable potential to grow. Korea is expected to have a huge growth potential since it has relatively higher level of information technology, fashion education system and activities than those of Japan in both the domestic diamond and international diamond. In particular, a better environment is laid out before Korea to gain competitiveness in the fashion industry due to the recently growing influence of the Korean Wave that Korea is expected to grow as a leader in the Asian market as well as in the global market.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.106-111
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• 2002

The estimation of pile bearing capacity is important since the design details are determined from the result. There are numerous ways of determining the pile design load, but only few of them are chosen in the actual design. According to the recent investigation in Korea, the formulas proposed by Meyerhof based on the SPT N values are most frequently chosen in the design stage. In the study, various static and dynamic formulas have been used in predicting the allowable bearing capacity of a pile. Further, the reliability of these formulas has been verified by comparing the perdicted values with the static and dynamic load test measurements. Also, in most cases, these methods of pile bearing capacity determination do not take the time effect consideration, the actual allowable load as determined from pile load test indicates severe deviation from the design value. The principle results of this study are summarized as follows : As a result of estimate the reliability in criterion of the Davisson method, t was showed that Terzaghi & Peck >Chin>Meyerhof > Modified Meyerhof method was the most reliable method for the prediction of bearing capacity. Comparisons of the various pile-driving formulas showed that Modified Engineering News was the most reliable method. However, a significant error happened between dynamic bearing capacity equation was judged that uncertainty of hammer efficiency, characteristics of variable, time effect etc... was not considered. As a result of considering time effect increased skin friction capacity higher than end bearing capacity. It was found out that it would be possible to increase the skin friction capacity 1.99 times higher than a driving. As a result of considering 7 day's time effect, it was obtained that Engineering news, Modified Engineering News, Hiley, Danish, Gates, CAPWAP(CAse Pile Wave Analysis Program) analysis for relation, repectively, $Q_{u(Restrike)} / Q_{u(EOID)} = 0.98t_{0.1}$ , $0.98t_{0.1}$, $1.17t_{0.1}$, $0.88t_{0.1}$, $0.89t_{0.1}$, $0.97t_{0.1}$.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.90-96
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• 1981

To design more efficient agricultural machinery, the accurately measuring system among many other factors is essential. A light-beam oscillographic recorder is generally used in measuring dynamic strain but it is not compatible with the extremely high speed measuring system such as 1,000 m/s, also is susceptable to damage due to vibration while using the system in field. The recorder used light sensitive paper for strip chart recording. The reading and analysis of data from the strip charts is very cumbersome, errorneous and time consuming. A microcomputer was interfaced with A/D converter, microcomputer program was developed for measuring, system calibration was done and the strain generated from a cantilever beam vibrator was measured. The results are summarized as follows. 1. Microcomputer program was developed to perform strain measuring of agricultural machine elements and could be controled freely the measuring intervals, no. of channels and no. of data. The maximum measuring speed was $62{\mu}s$. 2. Calibration the system was performed with triangle wave generated from a function generator and checked by an oscilloscope. The sampled data were processed using HP 3000 minicomputer of Chungnam National University computer center the graphical results were triangle same as input wave and so the system have been out of phase distorsion and amplitude distorsion. 3. The strain generated from a cantilever beam vibrator which has free vibration period of 0.019 second were measured by the system controlled to have l.0 ms of time interval and its computer output showing vibration curve which is well filted to theoretical value. 4. Using microcomputer on measuring the strain of agricultural machine elements could not only save analyzing time and recording papers but also get excellent adaptation to field experiment, especially in measurement requiring high speed and good precision.