• Journal of the Ergonomics Society of Korea
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• v.34 no.4
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• pp.313-326
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• 2015

Objective: The objective of this research is to quantitatively analyze muscle activities of arm and shoulder, according to direction in various types of one-handed manual material handling, based on surface electromyography. Background: Workers in industrial sites frequently carry out one-handed manual material handling using arm and shoulder muscles. Therefore, chronic load and accumulated fatigue occur to arm and shoulder muscles, which becomes a main cause of upper arm and shoulder musculoskeletal disorders. The shoulder muscles have widely range of motion, and complex interactions take place among various muscles including rotator cuff muscles. In this regard, research on interactions among should muscles, according to such various dynamic motions, is required. Method: Ten male subjects in their 20s participated in this research. This research considered upward, downward, leftward, rightward, forward and backward directions and fourteen muscles around arm and shoulder (biceps brachii and trapezius, etc.) as independent variables. The mean muscle activity was set as the dependent variable. This research extracted $4^{th}{\sim}7^{th}$ repetition signals according to ten times of repetitive muscle contraction, and analyzed the muscle activity concerned using the envelope detection technique. Results: The mean muscle activity of upward direction was analyzed highly statistically significant. The reason is that the effect of gravity works to arm and shoulder muscles. Also, it is conjectured that deformation of coracoacromial ligament was caused, and its contact pressure increased, due mainly to the shoulder flexion, and therefore load was analyzed high. Muscle activity was analyzed significantly low, according to concentric ballistic motion used in the concentric contraction phase by storing elastic energy in the eccentric contraction phase with a motion to bring the weight to the front of subject's body as to downward, leftward and backward directions. Because, elbow joint's flexion-extension motions mainly occurred, biceps brachii was analyzed high muscle activity as the prime mover. Conclusion: The information on the quantitative load of muscles can be applied to ergonomic work design for one-handed manual material handling to minimize muscle load. Application: This research has effectively identified muscle activity according to dynamic contraction by applying an envelope detection technique. The results can be used for ergonomic work design to minimize muscle load during the one-handed manual material handling, according to each direction. The research results are expected to be used for musculoskeletal disorder prevention and physiotherapy in the rehabilitation medical field, based on the muscle load of arm and shoulder in various directions.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.87-98
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• 2020

The bird track fossil site in Haman Formation is divided into seven sedimental layers by the sedimentary structures, lithofacies and sequences. The bird tracks top on the highest layer, which includes ripple marks and suncracks. The layer has lithofacies with reddish grey siltstone and dark grey mudstone, alternately. As an analysis for the same rocks of the fossil site, physical properties show on mean values for 0.62% of absorption rate, 1.64% of porosity and 2.63 of specific gravity. Rock-forming minerals composed mainly of plagioclase, quartz, calcite, chlorite and mica. Meanwhile, we executed an experiments based on the petrography and weatherings to find a proper consolidants. In the experiments, the OH 100 reagent proved stable aspect and the lowest transition rate in terms of weight and chromaticity. Also, it showed the highest increase in ultrasonic velocity, improving the physical properties of the rocks. In the case of applying the OH 100 with antihygro, an swelling inhibitors on the sedimentary rocks, the chromaticity indicated an stable transition aspect. When it comes to the physical properties, the antihygro also decreases the porosity effectively. Thus, the most proper method for the fossil site of Haman Formation is to apply antihygro and OH 100 reagents since the rocks includes clay minerals that show swelling characteristics. However, this result is deduced from an indoor application experiments, leaving the necessity of verification how these reagents would affect the bird tracks site under the field condition.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.1
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• pp.56-64
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• 2008

Although the EGSE (Electrical Ground Support Equipment) and MCS (Mission Control System) have many similar or even identical functions, the EGSE used for assembly, integration and validation phase and the MCS for the mission operations phase are normally developed separately and used by different groups of engineers. However, the common ground system for EGSE and MCS has developed and many space missions such as PROBA (PRoject for On-Board Autonomy), ROSETTA, MARS EXPRESS, CRYOSAT (Cryosphere Satellite), GOCE (Gravity field and steady state Ocean Circulation Explorer), and GALILEO have used or will use it to minimize risk, reduce cost and improve overall product quality. It is based on ECSS (European Cooperation for Space Standards) E70 which is the international standard for ground systems and operations published by ECSS E70 Working Group. The ECSS E70 contains the basic rules, principles and requirements applied to the engineering of the ground systems and the execution of mission operations. This paper introduces standardization policy, organization and standard documentation in ECSS. The overview of ECSS E70 such as status, purpose and contents is also described in this paper.

• Journal of the Korean Society of Costume
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• v.32
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• pp.163-182
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• 1997

The purpose of this study was intended to analyze artistic formativeness represented in the modern fashion design materials. Nowadays the modern fashion design materials is characterized by variety. The fashion materials the most important of fashion is called a softwear in textile industry and emerged as a new field. Fashion design also escaped from the tra-ditional restraint and extended to pursue lib-eral clothes and the designer's creative inten-tion has resulted in conceptual and conven-tional alteration as a new mode of plastic ex-preseeion. As a results of analysis of the formative fea-ture of Art style represented in the modern fashion design materials. First Surrealism had been searching for a new way of confronting a social and rtistic environment that was stifling and repugnant to them. Accordingly the wide applicaytion of the various object due to the thought of Sur-realism through the modern fashion materials brought the diversification and individua-lization of the modern fashion design. Second Pop Art that is made modern mech-anic culture and commercialism brought the great transformation in the history of Art out of the existing style and the sense of ex-pression. And the plastic characteristics of Pop Art that has a gravity as modern fashion materials on a them of the elements of popular consumer's society. That is the common and cheap objects were introduced into fashion materials itself or pat-tern. Third Minimalism is a trend in art att-empting to seek essence of the object by presenting simple and disciplined expressions by minimal formative means. The features of external form are simplicity clarity unrelated composition and symmetrical structure. Mini-malism was a quest for basic elements repre-senting the fundamental esthetic values of art. The minimal expression in modern fashion materials mean fabrics with simple surface and is contained using simple geometric pattern or utilizing textiles without any patterns. Fourth Eroticism is a kind of psychological revolution in the development of human civilization and is deeply rooted in the cultural tradition of myth religion customs and art. So Eroticism must be distinguished from a mere animal reproduction. These erotic char-acteristics were holded the meanings of sexu-ality through the modern fashion materials. Especially it was expressed the sexual part of body was nakedly showed through trans-parent materials or semitransparent like metalic and opaque materials. Recently the various kinds of new materials such as paper vinyle plastic metal as well as human body were applied to new fashion de-sign. First of all the new materials will give modern fashion designers stimuli and inspi-ration. It can also express values of moderners to despise materialism and uniformed modern society and to recover humanity and self-actualization.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.472-479
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• 2000

A persimmon harvesting vehicle that can be operated in hilly orchards as well as a manipulator that can be used to harvest persimmons located in remote positions in the trees were designed and developed. The vehicle could be operated with keeping balanced position in an inclined field and its working platform could be moved up and down easy to approach fruits in a remote region with the aids of a hydraulic and a electrical and electronics systems. The weight of the vehicle was 927 kg and the center of gravity was located at 427 mm to the inner side from the center of a right driving caterpillar, 607 mm to a rear axle from the center of a front axle, and 562 mm to upward from ground. The automatic level control sensor for leveling the working platform was activated within 14.5 ∼ 16.5 degrees of slope variation. The total length of the manipulator was 1.39 m and weight is 975 g. It was powered by a 12 V geared motor to detach persimmon fruits with a rotational force. The gripper was made of plastic and rubber to increase a frictional force. In a performance evaluation test, static tipping angle, dynamic tipping angle toward front side when the vehicle was moving downward, climbing angle, driving speed of the vehicle were measured or calculated. In persimmon harvesting tests 24.9% of yield was increased by hand picking with the aid of the vehicle and additional 7% of yield were increased when the manipulator was used. Therefore, 99010 of total possible yield was achievable when both of the vehicle and the manipulator were used for the manual persimmon harvesting. Increase in 22.5% of total yield was achieved with the manipulator only.

• The Korean Journal of Applied Statistics
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• v.33 no.5
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• pp.615-625
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• 2020

The document-term frequency matrix is a term extracted from documents in which the group information exists in text mining. In this study, we generated the document-term frequency matrix for document classification according to research field. We applied the traditional term weighting function term frequency-inverse document frequency (TF-IDF) to the generated document-term frequency matrix. In addition, we applied term frequency-inverse gravity moment (TF-IGM). We also generated a document-keyword weighted matrix by extracting keywords to improve the document classification accuracy. Based on the keywords matrix extracted, we classify documents using a deep neural network. In order to find the optimal model in the deep neural network, the accuracy of document classification was verified by changing the number of hidden layers and hidden nodes. Consequently, the model with eight hidden layers showed the highest accuracy and all TF-IGM document classification accuracy (according to parameter changes) were higher than TF-IDF. In addition, the deep neural network was confirmed to have better accuracy than the support vector machine. Therefore, we propose a method to apply TF-IGM and a deep neural network in the document classification.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.6
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• pp.361-374
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• 2016

When the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure is generated significantly due to pore volume change associated with rearrangement soil grains. This effect leads a seabed liquefaction around and under structures as a result from decrease in the effective stress, and the possibility of structure failure is increased eventually. These facts shown above have been investigated in the previous studies related to regular and irregular waves. This study suggested a concrete mat for preventing the seabed liquefaction near the submerged breakwater. The concrete mat was mainly used as a countermeasure for scouring protection in riverbed. According to installation of the concrete mattress, the time and spatial series of the deformation of submerged breakwater, the pore water pressure, and the pore water pressure ratio in the seabed were investigated. Their results were also compared with those of the seabed unprotected with the concrete mat. The results presented were confirmed that the liquefaction potential of seabed under the concrete mattress is significantly reduced under regular wave field.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.6
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• pp.1-12
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• 2005

Treatment level and pond reactions of a pond system were examined from May to October 2002. The system was constructed in July 2000 for purifying water of Sinyang stream that flows into Koheung Estuarine Lake located in the southern part of the Korean Peninsula. The system was composed of a primary and a secondary pond in series and established on the rice field near the lake. Water pumped from the stream was funneled into the primary pond, whose effluent was discharged into the secondary pond by gravity flow. Effluent from the secondary pond was funneled into wetlands. About 130 $m^3$/day of water was pumped into the primary pond and detention time of the primary and secondary pond was about 2 days. DO from the surface to the 1.0 m depth of the primary and secondary pond was in the rage of 5.2 to 11.0 mg/L and 4.3 to 0.7 mg/L, respectively. DO at the bottom layer of the primary pond was 0 mg/L and that of the secondary pond ranged 3.0~4.7 mg/L. The primary pond functioned as a facultative pond and the secondary as an aerobic one. The temperature difference between the surface and bottom layers of the ponds in August was about $2.5^{\circ}C$ and that in May and October was about $1.0^{\circ}C$. Thermocline was observed in the primary pond during the high ambient temperature of August. The sludge depth of the primary pond in May, August, and October was 2.4, 1.9, and 2.2 cm, respectively. That of the secondary pond was 1.2, 1.0, and 1.1 cm, respectively. SS, $BOD_5$, T-N, and T-P concentrations in influent averaged 16.64, 6.71, 6.21, and 0.23 mg/L and those in effluent from the primary pond averaged 11.48, 4.97, 4.81, and 0.17 mg/L, respectively. The removal rates of the primary pond for SS, $BOD_5$, T-N and T-P were 31%, 26%, 22%, and 24%, respectively. Average concentrations of SS, $BOD_5$, T-N, and T-P in effluent from the secondary pond were 9.81, 4.07, 4.03, and 0.14 mg/L, respectively and the abatement rates of the secondary pond for SS, $BOD_5$, T-N and T-P were 20%, 12%, 13%, and 15%, respectively. SS, $BOD_5$, T-N and T-P concentrations in effluent from the primary pond were significantly low(p=0.001) when compared with those from the secondary one.

• Journal of Distribution Science
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• v.17 no.3
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• pp.107-116
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• 2019

Purpose - Why, why is it difficult to predict the appropriateness of self-employment, and what are the countermeasures and policy proposals to overcome. This study intends to further develop the field of statistical variables. It is necessary to overcome the limitation of existing proper scale research in Korea. We need to find statistical variables that can determine the appropriateness of self-employment in Korea. These efforts will be helpful in evaluating OECD countries and statistics and developing domestic economic indicators. Research design, data, and methodology - It is the discovery of statistical indicators and complementary indicators that have not been revealed in previous studies. Therefore, we sought to find new statistical parameters based on the statistics of the Korea National Statistical Office, the Bank of Korea, and overseas OECD statistics. (Proper Size of Adequacy) is defined as the specific gravity or number of the self-employed in Korea, which is shown as "Out Put" by statistical analysis of STATA panel statistical data. It is possible to further develop variables such as gross domestic product, gross national product, economic growth rate, unemployment rate, income tax rate, consumer price, tax level, exports, import amount, bill default I want to dig. Results - In addition to expanding economic indicators that can be explained by self-employment determinants, we have developed a variety of methods such as linear and non-linear (U-shaped, inverted U-shaped). It is the improvement of the self-employment determinants and the analysis method to estimate the appropriate scale. Conclusions - The proposed contents are reflected in self - employment appropriateness evaluation data and hope to help the government to select the policy support and to evaluate the government business after the policy support. These efforts are expected to be of great help to operators operating their own businesses, and to government and related institutional practitioners who support them. In this way, self-employment will be created in accordance with the Korean situation, where the happy life of all the people becomes the premise and the inclusive economic activities are guaranteed. It will improve the method of analyzing proper scale of small business owners and self-employed in Korea.

• Journal of the Korean GEO-environmental Society
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• v.11 no.5
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• pp.25-34
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• 2010

In this study characteristics for reclaimed ash was studied to enlarge the usage of reclaimed ash which is reaching to 72 million ton producted from whole thermal power plants in South Korea. Fly ash and bottom ash are reclaimed separately at some of thermal power plants. However, typically bottom ash and fly ash are mixed when they are buried at most of the thermal power plant, as a result the engineering characteristics of ponded ash are not investigated properly. In order to investigate the engineering characteristics of the ponded ash, laboratory tests were performed with ponded ash and fly ash from youngheung and samcheonpo thermal power plants. Specific gravity, unit weight, and grain size analysis test were fulfilled to evaluate the physical characteristics and triaxial permeability test, direct shear test, unconfined compressive strength test, compaction test were performed to evaluate the mechanical characteristics. And also engineering characteristics of coal ash from anthracite and Bituminous thermal power plants were compared and studied respectively. As a result of the study, it was confirmed that using coal ash from Bituminous thermal power plants can be effective in the place where lightweight materials are required and using coal ash from anthracite thermal power plants can be effective as backfill material which require higher permeability. Finally, it was confirmed that fly ash from youngheung thermal power plants which has the lowest permeability among the tested material is suitable for a field requiring impermeable material.