• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.131-138
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• 2018

In this study, we investigated the trend of technological development in major countries related to the propulsion equipment of railway vehicles. The propulsion system is the main equipment of electric vehicles. A lot of time and investment are required in order to ensure the development of technology. Therefore, developed countries have maximized their effort to develop technologies with safety, reliability, and convenience of maintenance. They have also done their utmost to prevent technology transfer to other countries after the development of new technologies. For example, Toshiba of Japan developed a new 3,300V/1,500 A class IGBT power device, but was reluctant to export it to foreign countries in order to protect this technology. In this study, we analyzed the patents applied for related to propulsion control systems and presented the direction of development during the technical development of these systems. The patent analysis of the core technologies was conducted using the Thomson Innovation DB. We examined the number of patents applied for by country, year and major applicant. As a result of the analysis, it was found that the proportion of patent applications per country was in the order of China, 48%, Europe 16.6%, and the United States 14.9%. The patent situation of the top 10 principal applicants revealed that (the top three were?) ABB 14%, GE 13%, and CRRC 12%. At the same time, we also conducted a qualitative analysis of the level of technical development by evaluating such factors as the influence index, quotation, market securing power and citation. Based on the result of the patent analysis, we presented the direction of technical development of the propulsion control equipment of railway vehicles. Based on the analysis results, it was found that domestic applicants considerably reduced their efforts to protect their patents from foreign companies. Nowadays, most of the electric motors used in Korea are induction motors. In advanced countries, permanent magnet electric motors are employed in new railway lines. Therefore, intensive investment is needed in new developments.

• Journal of Bio-Environment Control
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• v.22 no.3
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• pp.284-290
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• 2013

This study analyzed the geometric, compressive, cutting and friction properties of oriental melons in order to design a gripper capable of soft handling and a cutter for cutting oriental melon vine among the end effector of oriental melon as a preliminary step for developing the end effector of the robot capable of harvesting oriental melons in protected cultivation. As a result, the average length, diameter at the midpoint, weight, volume and roundness of the oriental melons were 108 mm, 70 mm, 188 g, 333 mL and 3.8 mm. Nonlinear regression analysis was performed on the equation $W=L^a{\times}D_2^b$ with variation of the length (L) and diameter (D2) of the weight (W) of the oriental melons. As a result, it was shown that there was a correlation between a of 2.0279 and b of -0.9998 as a constant value. The average diameter of the oriental melon vine was 3.8 mm, and most vines were distributed within a radius of 5 mm from the center. The average yield value, compressive strength and hardness of the oriental melons were $36.5N/cm^2$, $185.7N/cm^2$ and $636.7N/cm^2$, respectively. The average cutting force and shear strength of the oriental melon vines were $2.87{\times}10^{-2}\;N$ and $5.60N/cm^2$, respectively. The maximum friction coefficient of the oriental melons was rubber of 0.609, followed by aluminium of 0.393, stainless steel of 0.177 and teflon of 0.079. It was considered possible to apply it to the size of the gripper and cutter, turning radius, dynamics of drive motor and selection of materials and their quality in light of the position error and safety factor according to the movement when designing end effector based on the analyzed data.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.71-81
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• 2005

The purposes of this study was to collect, analyze, and describe the MF exposure levels from subways in Korea and to measure and evaluate the MF levels generated from electric appliances used at general homes. The target subway lines were Seoul Metropolitan Line 1 to Line 8, Bundang Line, Incheon Line, Daegu Line, Gwangju Line, and Busan Line 1 and Line 2. We measured at each station in those subway lines and, all the train types (pantograph-equipped, motor-equipped, and common), and platform types(facing and isolating) were investigated by the distance(80, 200, 400 cm) from the train on 19 targeted subway lines using 3 magnetic field measuring devices (EMDEXII, Enertech Co.) during the survey from January till October, 2004. On the other hand, the levels of the 60Hz magnetic fields generated from 14 items of home electric appliances such as electric blankets, hair dryers, electric razors, etc. were measured at 10 general homes using 5 EMDEXII meters with a sampling interval of 1.5 second by the distance(surface, 30, 50, 100, 300cm ) from the target electric appliances. The survey results in the whole subway lines examined in this study were as follows; Seoul Metropolitan Line 4 using AC(alternating current) power source showed the highest mean value of $2.85{\mu}T$, followed by Seoul Metropolitan Line 1 running between Seoul and Incheon using AC($2.78{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Uijongbu using AC($2.73{\mu}T$), Bundang Line using AC($1.79{\mu}T$), Seoul Metropolitan Line 1 connected from Yongsan using AC($1.67{\mu}T$), Seoul Metropolitan Line 1 between Seoul and Suwon using AC($0.79{\mu}T$), and so on. In general, the intensity of the magnetic field in the subway systems in Korea was significantly higher when using AC($2.14{\pm}0.91{\mu}T$) than when using DC($0.29{\pm}0.44{\mu}T$) power source. Among the home electric appliances examined, microwave ovens showed the highest mean value of $7.69{\mu}T$, followed by hair dryers($6.47{\mu}T$), vacuum cleaners($5.27{\mu}T$), televisions ($2.26{\mu}T$), electric blankets($1.38{\mu}T$), personal computers ($0.81{\mu}T$), and so on. Two items of electric appliances showed the excess value of $0.2{\mu}T$ at the distance of 30cm in the MF exposure level; electric razors $1.58{\pm}2.13{\mu}T$ and vacuum cleaners $0.48{\pm}0.44{\mu}T$. As a whole, this study showed a tendency that the shift of the MF levels according to the increase of distance from the electric appliances was lower than those of the results surveyed in UK and USA. As a result, this study is expected to suggest meaningful data for the future study in exposure assessment of magnetic fields and for the establishment of guidelines for subways and electric appliances in Korea. More detailed and large scaled exposure assessment studies should be performed continuously to get the various and useful information on health risk assessment of MFs in Korea.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.88-89
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• 2013

A variety of influenza A viruses from animal hosts are continuously prevalent throughout the world which cause human epidemics resulting millions of human infections and enormous industrial and economic damages. Thus, early diagnosis of such pathogen is of paramount importance for biomedical examination and public healthcare screening. To approach this issue, here we propose a fully integrated Rotary genetic analysis system, called Rotary Genetic Analyzer, for on-site detection of influenza A viruses with high speed. The Rotary Genetic Analyzer is made up of four parts including a disposable microchip, a servo motor for precise and high rate spinning of the chip, thermal blocks for temperature control, and a miniaturized optical fluorescence detector as shown Fig. 1. A thermal block made from duralumin is integrated with a film heater at the bottom and a resistance temperature detector (RTD) in the middle. For the efficient performance of RT-PCR, three thermal blocks are placed on the Rotary stage and the temperature of each block is corresponded to the thermal cycling, namely $95^{\circ}C$ (denature), $58^{\circ}C$ (annealing), and $72^{\circ}C$ (extension). Rotary RT-PCR was performed to amplify the target gene which was monitored by an optical fluorescent detector above the extension block. A disposable microdevice (10 cm diameter) consists of a solid-phase extraction based sample pretreatment unit, bead chamber, and 4 ${\mu}L$ of the PCR chamber as shown Fig. 2. The microchip is fabricated using a patterned polycarbonate (PC) sheet with 1 mm thickness and a PC film with 130 ${\mu}m$ thickness, which layers are thermally bonded at $138^{\circ}C$ using acetone vapour. Silicatreated microglass beads with 150~212 ${\mu}L$ diameter are introduced into the sample pretreatment chambers and held in place by weir structure for construction of solid-phase extraction system. Fig. 3 shows strobed images of sequential loading of three samples. Three samples were loaded into the reservoir simultaneously (Fig. 3A), then the influenza A H3N2 viral RNA sample was loaded at 5000 RPM for 10 sec (Fig. 3B). Washing buffer was followed at 5000 RPM for 5 min (Fig. 3C), and angular frequency was decreased to 100 RPM for siphon priming of PCR cocktail to the channel as shown in Figure 3D. Finally the PCR cocktail was loaded to the bead chamber at 2000 RPM for 10 sec, and then RPM was increased up to 5000 RPM for 1 min to obtain the as much as PCR cocktail containing the RNA template (Fig. 3E). In this system, the wastes from RNA samples and washing buffer were transported to the waste chamber, which is fully filled to the chamber with precise optimization. Then, the PCR cocktail was able to transport to the PCR chamber. Fig. 3F shows the final image of the sample pretreatment. PCR cocktail containing RNA template is successfully isolated from waste. To detect the influenza A H3N2 virus, the purified RNA with PCR cocktail in the PCR chamber was amplified by using performed the RNA capture on the proposed microdevice. The fluorescence images were described in Figure 4A at the 0, 40 cycles. The fluorescence signal (40 cycle) was drastically increased confirming the influenza A H3N2 virus. The real-time profiles were successfully obtained using the optical fluorescence detector as shown in Figure 4B. The Rotary PCR and off-chip PCR were compared with same amount of influenza A H3N2 virus. The Ct value of Rotary PCR was smaller than the off-chip PCR without contamination. The whole process of the sample pretreatment and RT-PCR could be accomplished in 30 min on the fully integrated Rotary Genetic Analyzer system. We have demonstrated a fully integrated and portable Rotary Genetic Analyzer for detection of the gene expression of influenza A virus, which has 'Sample-in-answer-out' capability including sample pretreatment, rotary amplification, and optical detection. Target gene amplification was real-time monitored using the integrated Rotary Genetic Analyzer system.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.2
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• pp.40-68
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• 2001

In this study, grade of subjective symptom appealed by laborer of Jeollabuk-do was evaluated using questionary regarding factor made effect on musculoskeletal disease and in addition, studied relationship with health promotion life style of them. Based on the result, relationship of general characteristics of musculoskeletal subjective symptom and life-style of the subjects was concluded as below. 1. General characteristics of study subjects were as following. Ratio of male was higher as 57.7% of male and 42.2% female and age distribution was 5.1% of 20s, 34.99% of 30s, 36.3% of 40s and 23.7% of 50s and therefore, $30{\sim}40$ aged groups showed highest ratio. Most subjects (74.9%) was married status and in case of education level, high-school graduate and dropout (23.3%) and over-college graduate (46.8%) showed highest distribution. $1{\sim}2$ Mil. KRW (29.5%) and $2{\sim}2.99$ Mil. KRW (21.2%) is the main income distribution and however there was high ratio of non-reply (29.0%). In case of employment period, $10{\sim}14$ years (15.3%) and over 15 years (29.6%) showed highest ratio and there were many non-reply (39.4%) and in addition, 67.6% replied as own house and 14.3% as lease on deposit base in question of residence type. 2. Subjects showed high ratio of subjective symptom appeal of 62.79% and many cases (50.23%) appealed 1 or 2 symptoms. Symptom by body region was 29.8% (waist), 27% (shoulder), 21.2% (knee), 15.5% (neck), 9.5% (ankle), 8.1% (wrist) and 5.0% (elbow) in order. In case of relationship with general characteristics, female comparing with male, non-residence of own house, subjects with lower education level and employment period of $10{\sim}14$ years showed higher appeal rate and kind of symptoms than others. Therefore, it was concluded that rate of musculoskeletal symptom appeal have close relationship with gender, level of living, education level, age and employment period. 3. In case of severe pain of upper body except waist and ankle, it was appealed in both or right side and it means that upper body pain is originated from right side and right region pain is transited to both region pain. In addition, there was 39.41% of non-reply to existence of right-left region pain and therefore, it was evaluated that, in may cases, there was no awareness of their own symptom condition even on subjective symptom. 4. Degree of pain was, as pain over middle level, evaluated as 2.79 on full mark of 4.0 and in order of waist (2.97), ankle (2.83), knee (2.82), wrist (2.82), neck (2.79), shoulder (2.70) and elbow (2.62). In addition, 71.97% appealed $2{\sim}3$ cases for the latest 1 week. Owing to subjective symptom, 54.95% drop into hospital or pharmacy, 10.32% made temporary retirement or absence, 7.99% transferred into more comfortable duty and $39.4{\sim}54%$ experienced one or more managing mentioned above. 5. Fulfillment of health promotion life style of subjects was evaluated on full mark of 4.0 and total score was 2.63. Average mark of each area was personal relationship (3.05), self-realization (2.92), stress management (2.63), health control (2.48), physical exercise (2.19) and nutrition management (2.19) and personal relationship was highest and physical exercise and nutrition management were lowest. As general characteristics influencing health promotion life style, gender, residence style and employment period showed significant difference. Male showed higher mark than female and showed higher mark in order of own house, others, lease on deposit base, monthly rent. Subjects with longer employment period showed higher mark with significant difference. 6. Accounting of factor influencing each area of health promotion life style, self-realization showed significance in marriage status, income, residence style and education level and health control in age, residence style and employment period. Physical exercise showed significant difference in gender, age, residence style and employment period and nutrition in gender, age, residence style and employment period. Stress management showed significant difference in residence style and employment period and however not in personal relationship. 7. Health promotion life style relating with existence and kind of pain showed significant difference in all area except personal relationship area. In absence of pain, there was statistically significant high score in all area even in total health promotion life style and all area. Accounting of kind of pain, cases of $1{\sim}2$ kinds of pain and $5{\sim}6$ kinds of pain showed relatively high score and it was lower than mark of subject stated absence of pain. 8. Subjects appeal symptom were classified by symptom region and difference of total and each areas were evaluated. General area (p=0.002), self-realization (p=0.012), health management (p=0.023), physical exercise (p=0.028), nutrition management (p=0.028) and stress control (p=0.001) showed statistically significant difference and not in personal relationship area. Especially, elbow, shoulder and neck area marked high and group appealed pain of knee, arm and elbow, foot and ankle marked low. Based on those results, subjective symptom should be accounted seriously in diagnosis of occupational musculoskeletal disease of laborer and among subjective symptom, general characteristics of gender, age, condition of living, education level and employment period make effect. Generally subject appeal symptom marked lower than subject without symptom appeal and it means that life management of subject appealing musculoskeletal pain make important role in management and treatment of occupational musculoskeletal disease.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.2
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• pp.69-92
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• 2001

The purposes of this study were to offer foundation making more certain standards of musculoskeletal disorder diagnosis, We researched musculoskeletal symptoms degrees, frequencies, and cares and then examined relation between musculoskeletal symptoms and diagnosis of musculoskeletal conditions using moire topography among workers at an automobile manufacturing plant. Therefore we propose the possibility of moire topography as diagnosing utilities of musculoskeletal disorders. Methods: This study was to examine the general characteristics, complaints of musculoskeletal symptoms, and work-related musculoskeletal disorder rates of cervicobrachial and lumbar area by survey among 435 workers at an automobile manufacturing plant and then to show each frequency and percentage, In the diagnosis using moire topography, we studied pain control necessity of cervicobrachial and lumbar area, 435 subjects were classified by 5 levels: A(no symptoms), B(need management), C(need treatment) and then more divided by B1(light symptoms)/B2(heavy symptoms), C1(light symptoms)/C2(heavy symptoms), And musculoskeletal areas were divided by 2 parts, cervicobrachial area(neck, shoulder, arm&elbow, and wrist&hand) and lumbar area, Then, frequency and percentage of each musculoskeletal areas(cervicobrachial and lumbar area) were appeared. At last, Pearson's chi-square test analysis was utilized to observe the relation between diagnosis using moire topography and general characteristics and the relation between diagnosis using moire topography and work-related complaint of musculoskeletal symptoms of cervicobrachial and lumbar area, Results: The subjects employed for this research were categorized into; by gender, all of them were males(l00%): by age, under 35 years 12 %, 36-40 years 56.3%, 41-45 years 26.3 %, and above 46 years 5.3% with 36-40 years accounting for most of it. By living location, owned houses represented 69.7%, rented houses 23.4%, monthly-rented 1.6%, the others 5.3%; by education, middle school and lower represented 3.0%, high school 89.4%, and junior college and higher 7.6% with high school occupying most of the group. By marital status, married represented 95.2%, unmarried 4.1%, and the others 0.7% with most of them married; by alcohol, drinking represented 81.8% and non-drinking 18.2%; by smoking status, smoking represented 53.6%, non-smoking 46.4% with no big difference between them. By working time(hours/week), below 50 represented 26.9%, 50-60 67.6%, above 60 5.5%; by working time(hours/day), below 9 represented 21.6%, 10-12 73.1%, above 13 5.3%; by job tenure(years), below 10 represented 25.1%, 11-15 54.3%, 16-20 15.2%, above 21 5.5%. By personal income per year, below 30 million won represented 11.0%, 30-40 84.8%, above 40 4.1%; by sleeping hours, below 6 hours represented 26.7%, 7-8 hours 69.9%, above 9 hours 3.4%. Complaint rates of musculoskeletal symptoms and work-related musculoskeletal disorder rates were 63.9% and 54.9% with shoulder area occupying most of both them. By pain degree of musculoskeletal symptoms, shoulder area represented $2.73{\pm}0.84$, lumbar area $2.66{\pm}0.86$, wrist and hand area $2.59{\pm}0.86$, neck area $2.55{\pm}0.74$, and arm and elbow area $2.48{\pm}0.71$. By cares about musculoskeletal symptoms, taking medication or care represented 34.4%-46.7%, absence or leave 15.4%-28.7%, and job transfer 6.3%-11.5%. So experienced cases more than one thing among cares about musculoskeletal symptoms represented 39.6%-54%. In the diagnosis using moire topography, pain control necessity of cervicobrachial area was shown below; A(no symptoms) 20.7%, B1(need management/light symptoms) 64.6%, B2(need management/heavy symptoms) 11.5%, C1(need treatment/light symptoms) 3.0%, C2(need treatment/heavy symptoms) 0.2%. By lumbar area, A(no symptoms) 8.7%, B1(need management/light symptoms) 52.2%, B2(need management/heavy symptoms) 30.3%, C1(need treatment/light symptoms) 8.7%, C2(need treatment/heavy symptoms) was none. In the relation between pain control necessity and general characteristics, age(P=0.013), education(P=0.000), and job tenure(P=0.012) with pain control necessity showed differences with significance. The relation between pain control necessity and complaint of musculoskeletal symptoms of cervicobrachial and lumbar area showed no difference with significance; in cervicobrachial area represented P=0.708, lumbar area P=0.318 Conclusions: This study for musculoskeletal symptoms on workers at automobile manufacturing plant showed that complaint rates of musculoskeletal symptoms for cervicobrachial and lumbar area were so high, 63.9%. But Pearson's chi-square test analysis was utilized to study the relation between musculoskeletal symptoms and the diagnosis using moire topography, showed no differences with significance. They have no differences with significance, but the prevalence rates of diagnosis using moire topography for cervicobrachial and lumbar area were more higher than complaint rates of musculoskeletal symptoms; complaint rates of musculoskeletal symptoms were 52.4%, 34.5% and the diagnosis using moire topography were 79.3%, 91.3% for cervicobrachial and lumbar area. The results of this study indicate that the diagnosis using moire topography can find weak musculoskeletal disorders that an individual can not feel, not be judged work-related musculoskeletal disease. Therefore, this study has an important meaning that diagnosis using moire topography can predict and control own physical condition complete musculoskeletal disorders beforehand, since oriental medicine theory considers that prevention is important.