• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.183-194
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• 1992

Some silicon micromechanical structures useful in sensors and actuators have been fabricated by electropolishing or porous silicon formation technique by anodic reaction in HF solution. The microstructures were lightly doped single crystal silicon and the formation was isotropic independent of crystal directions. Porous silicon layer(PSL) was formed selectively in $n^{+}$ region of $n^{+}/n$ silicon structure by anodic reaction in concentrated HF(20-48%) solution. Characteristics of the formed PSL were investigated along with change of the reaction voltage, HF concentration and the reaction time. PSL was formed only in $n^{+}$ region. The porosity of the PSL was decreased with the increase of HF concentration and independent of reaction voltage. For the case of $n/n^{+}/n$ structures, the etched surface of silicon was fairly smooth and a cusp was not found. The thickness of the microstructures was the same as that of the epitaxial n-Si layer and good uniformity. We have fabricated acceleration sensors by anodic reaction in HF solution(5 wt%) and planar technology. The process was compatible with conventional It fabrication technique. Various micromechanical structures, such as rotors of motor, gears and linear actuator, were also fabricated by the technique and examined by SEM photographs.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.41 no.3
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• pp.188-198
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• 2005

This study was conducted to survey the catches of vertical bottom longline fisheries in the sea mount of central northern Pacific($30^{\circ}-42^{\circ}N$, $170^{\circ}-175^{\circ}E$), during the period of July 1 to August 25,2004 by commercial fishing vessel. The number of 57 test fishing was carried out in the central northern Pacific during 43 days and the total catches were 21,092.4kg as 19 fish species, CPUE/day and catches/day were 185 baskets and 490.5kg, respectively. Main fish species caught from the experimental fishing were Squalus mitsukurii (66.3%), Coelorhyrchus asperocephaius (11.7%) and Helicolenus avius (9.8%) and, average inside diameter for fish mouth was 4.0cm over. Catch ratio according to each fishing ground was the order of F, D, J, B and C. Catch ratio fur water depth was the order of 450-500m, 350-400m, 300-350m, 400-450m, 1000-1100m and 500-550m and, main species by water depth was Squalus mitsukurii for 300-400m, Etmopterus lucifer for 300-550m, Coelorhyrchus asperocephaius far 1,000m over. Catch ratio according to the kind of hooks was higher at the hook no.6 for Squalus mitsukurii and no. 5 for Etmopterus lucifer and, catch ratio by baits was higher at squid for Squalus mitsukurii, saury and eel for Helicolemus avius and saury for Etmopterus lucifer. Accordingly, it is thought that the extension of fishing hours is needed with the reduction of damage and loss for fishing gears during fishing operation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.148-154
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• 2007

This study investigated the spatial distribution of the marine debris in Jinudo in the Nakdong river estuary. Types of marine debris in Jinudo are analyzed through sampling around some portion of its sandbar shoreline. The present study and its main results are summarized as follow: 1) Monitoring system, for evaluating the volume of marine debris, was established in the coastal region of $50\;m\;{\times}\;50\;m\;(=0.002\;km^2)$ over the southern part of Jinudo. All the marine debris of conceivable form are collected and their amount was also estimated. 2) During the $1^{st}$ collection in May 2007, the total weight of the marine debris was 1,110 kg in this site, which means the density of marine debris around the shoreline is $444\;ton/km^2$. After one month later, the collected marine debris was 23.75 kg and so we have the average density of $9.5\;ton/km^2$. From these results, it is suggested that the marine debris of 316.67kg was being accumulated per day over unit area($1\;km^2$). 3) The most frequent marine debris collected during monitoring campaigns was wooden material amounting to 85.86% of the whole collection; the rest were fishing gears such as nets and buoys(5.13%), household waste(2.34%), glass(0.94%) and metals(0.27%).

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.245-256
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• 2006

Fish community in the Hoengseong Reservoir was investigated from April to October 2005. The total number of fish caught from the period was 8,626 fish representing 22 species and 8 families, using tyke net and trammel net. Besides biomass was 122.9 kg. In the fyke net, 8,168 individuals caught during the period represented 21 species belonged to 8 families, its biomass was 90.6 kg. On the other hand, 458 individuals caught in the trammel net during the period represented 16species belonged to 6 families, its biomass was 26.3 kg. The results showed that the trammel net had lower number of species, individuals, and less biomass compared to those of the tyke net. Number of species confirmed was increased according as mesh size of the net was smaller. Besides, the fyke net with small mesh size was able to collect not only small-sized fish but also large-sized fish so that it was suitable to study qualitative and quantitative analysis of fish fauna in detail. Whereas, the trammel net with proper mesh size was effective to determine composition of fish species in the studied area.

• The International Journal of Costume Culture
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• v.4 no.1
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• pp.25-33
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• 2001

This study is to analyze Korean-Chinese women's Costume in Yabian with factors such as reform opening-up, economic growth, change of social values, development of technology, more education opportunities and influence of mass media. It divides the 1990's into two halves. Photos, interview, observation and relevant literature were used for this study. Even though economy grew rapidly, they needed to purchase daily goods other than clothes. In a way that they preferred practicality, it showed somewhat it was still developing. The trend in the first half of the 1990's was characterized : first, Synthetic or artificial fibers and ready-made suits were popular ; second, there still remained the men's style ; third, they wore Tanrikoo(彈力袴), Tisingkoo(體型袴), Jiaotakoo(脚袴) because of its properties of activeness and comfort ; fourth, shoulders looked ore prominent with pads as they were used in Chungsanfoo(中山服) ; fifth, clothes in grey and dark blue was in fashion ; sixth, they wore hand-made knit vests and sweaters and often mountain-climbing gears for its light and warm quality ; seventh, along with opening-up, various materials and colorful clothes were in style, which satisfied women's desire for beauty. They decorated Hanbok(韓服), using sleeves with colors, golden ornaments, flower patterns embroidery, materials of different color in collar and tie and dyes of sleeves and skirts. In the first half of the 1990's when the opening-up was beginning, there were diverse styles and colors in fashion, yet not close to good quality. As the economy grew, the second half of the 1990's was characterized by good palate, individuality, favouritism on foreign goods, rapid change of fashion. For instance, fur coat and woolen fabric were favored. Economic growth led to abundance of cloth, dyes and decorative materials. In addition, people possessed more clothing and it was possible for them to wear both Hanbok and wedding dress in wedding ceremony. People placed their standards on competency and financial ability rather than ideology. Worship disappeared and individuality arose. Therefore, apparel functioned not only as protection but as suits with aesthetic purpose. This resulted in introduction of bold style, imitation of western countries and extension of use of Hanbok. With the help of mass media, transportation, telecommunication, contact with Korean company and civilians, Korean and western cultures, through Korea, were accepted. Change in structure of economic status caused excessive spending and more educational opportunities that enabled people to accept foreign culture quickly. Values moved onto new, beautiful and better characteristics. it was possible to have suits ready-made due to improvement of mass production and cotten, wool, linen, silk became popular owing to technology. New technology, the bases of mass consumption, increased possession of clothing and accelerated change of fashion. In summary, women's Costume in Yanbian were affected by the factors in economy, politics, culture contact as well as change of society and technology.

• Journal of the Korea Society for Simulation
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• v.24 no.1
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• pp.35-43
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• 2015

This research proposed a new method to evaluate the objective validity to launch smart transportation services that various stakeholders are complicatedly inter-connected. First of all, we have designed the fundamental business model to form the smart transportation services and defined the stakeholders taking part in the services. Also, the criteria to evaluate the economical validity has been proposed based on the relationship among stakeholders. Especially, in the case EV drivers and charging service providers, the economical validity depends on the scale of spreading. Therefore, we have compared the two extreme scenarios, the poor and stable level of EV spreading. According to the result, it may be said that EV drivers and charging service providers cannot be guaranteed the economical validity due to the burden of initial investment. On the contrary to this, suppliers of EV and charging gears may secure more than a certain level of profit. In addition, the government may have great profit due to reducing the CO2 emission and cost for importing energy sources. Therefore, it is needed to enhance the level of supporting EV drivers and charging service providers at the first stage. Also, the impact of the ratio of EV and charging service stations on the economical validity of smart transportation should be further investigated.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.7
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• pp.56-64
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• 2012

A smart grid is the next generation power grid which combines the existing power grid with information technology, so an energy efficient power grid can be provided. In this paper, in order to build an efficient smart grid an AMI system, which gears with the existing home network and provides an user friendly management function, is proposed. The proposed AMI system, which is based on an extended home network, consists of various functional units; smart meters, communication modules, home gateway, security modules, meter data management modules (MDMM), electric power application modules and so on. The proposed home network system, which can reduce electric power consumption and transmit data more effectively, is designed by using IEEE 802.15.4. The extended home gateway can exchange energy consumption information with the outside management system via web services. The proposed AMI system is designed to enable two-way communication between the home gateway and MDMM via the Internet. The AES(Advanced Encryption Standard) algorithm, which is a symmetric block cipher algorithm, is used to ensure secure information exchange. Even though the results in this study could be limited to our experimental environment, the result of the simulation test shows that the proposed system reduces electric power consumption by 4~42% on average compared to the case of using no control.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.6
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• pp.8-14
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• 2017

Gearboxes for power transmission of a rotorcraft transfer power generated by an engine to the fan and the pusher for up, down and forward flight. The gearboxes are divided into the main gearbox and the sub-gearbox. The main goal of the gearbox design is to design the weight as light as possible within a range that satisfies all given requirements (transmission power, mounting space, etc.). In particular, the initial conceptual design is very important to reduce the weight of the gearbox, since the weight can vary greatly depending on the system configuration, even if it has the same function. In this study, various conceptual designs of the gearbox according to the installation position of the engine were presented. Also, the element parts such as gears and bearings in each concept design were designed by sizing for their life, and the estimated weights of the conceptual system configuration were compared.

• The Journal of Fisheries Business Administration
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• v.35 no.1
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• pp.23-56
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• 2004

The offshore trawl fishery is seeking its survival way to overcome current management conditions in red, resulted from the bilateral agreement with China and Japan. However, this movement magnifies conflicts between fisheries on the contrary and it is thought to be impossible to get over current situations. For all that, this study is aimed at investigating how this current situations have occurred. The management freedom as response to the change in fishing conditions of a certain fishery, in case of Korea, is affected by institutional regulations. The example of this is controls on fishing gears, fishing vessels, and fishing grounds. The most exposure of this control is a segmentation of institutional fisheries. The initial segmentation of the offshore trawl fishery in Korea was occurred in the period of Japan's colonization when the degree of use of fishing grounds was limited geographically. At that time, fisheries were divided by fishing areas, but it did not divide the fishery itself. The large - sized fishing vessels were developed politically to be more competative to Japanese fishing vessels since 1950s. During this time, the trawl fishery was merged into current Eastern trawl fishery and South - Western trawl fishery. It was also inevitable to divide into the pair trawl and single trawl fishery as a result of the physical mergency between Western trawl and Southern trawl fishery. In order to develop the trawl fishery, new licenses were issued on the shrimp trawl fishery, through which it was expected to boost the trawl fishery. As opposed, the shrimp trawl fishery was changed into the mid - sized trawl fishery, targeting on the eastern fishing areas and the large - sized trawl fishery was developed since the late of 1970s with the development of filefish processing industry. The large trawl fishery that led in development of offshore trawl fishery since the late of 1950s was started to divide into a pair trawl and single trawl according to the fishing method and capital power. It finally became an institutionally independent fishery in 1980s, respectively. Looking into these historical process, the segmentation of the trawl fishery is thought as a result of the lack of long - term perspective and as a production of trial and error resulted by unprepared policy. As a result, these segmentation of fisheries roles as critical obstacles in harmonization of fisheries and in overcoming of current situations. Therefore, the review of this institutional segmentation of the offshore trawl fishery should be taken for an optimal redistribution of fishing grounds suits with business and fishing technology. For this, the fishery must be divided into large capitalized fishery and small - mid fishery with consideration of capital, fishing method, and the condition of use of fishing grounds. In addition to this, by limiting outline of fishing ground that the large fishery can harvest, it must allow for the small - mid fishery to catch with its own boundary. Furthermore, by launching buyback programs on the trawl, eastern trawl, pair trawl, it can provide broader fishing grounds where the fishery can harvest with management freedom.

• Journal of Digital Contents Society
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• v.10 no.2
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• pp.199-207
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• 2009

The Q-switching the shutter or the different optical science element puts in within the laser light resonator and the storehouse departs from the within the resonator it loses the mortar and the reversal distribution which when is sufficient creates from within the active medium, opens the shutter instantaneously and it is to do to be made to emit with the light where the energy which is accumulated within the resonator is strong very. Like this Q-switching of laser resonator--It decreases factor increasing suddenly to make. To method of Laser Q-switching mechanical switching methods, electro-optic switching methods and switching by saturable absorber methods, acousto-optic switching method etc. 4 kind are being used on a large scale. In these people the conversion which is electric in compliance with the effect which is electrooptics is widely being used the Q-switching pulse of short pulse width because being it will be able to create. Consequently, Pockel cell where it has the quality of electrooptics effect) the Q-it is become known that it is suitable it uses with switch. From the research which it sees FET and one-chip microprocessor where it is a switching element and pulse transfomer to plan and produce pockel cell Q-switch driving gears, pulse style Nd: It applied in YAG Laser system and it investigated and researched the operating characteristic of the Q-switch. Also, the Q-switch leads and Nd where it is output: YAG with forecast in compliance with a theoretical calculation it comes to buy laser beam side politics it compared and laser beam qualities which had become Q-switching it analyzed.