• Journal of the Ergonomics Society of Korea
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• v.34 no.2
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• pp.85-101
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• 2015

Objective: The purpose of this study was to develop and evaluate smart secondary controls using iPad for the drivers with physical disabilities in the driving simulator. Background: The physically disabled drivers face problems in the operation of secondary control devices that accept a control input from a driver for the purpose of operating the subsystems of a motor vehicle. Many of conventional secondary controls consist of small knobs or switches that physically disabled drivers have difficulties in grasping, pulling or twisting. Therefore, their use while driving might increase distraction and workload because of longer operation time. Method: We examined the operation time of conventional and smart secondary controls, such as hazard warning, turn signal, window, windshield wiper, headlights, automatic transmission and horn. The hardware of smart secondary control system was composed of iPad, wireless router, digital input/output module and relay switch. We used the STISim Drive3 software for driving test, customized Labview and Xcode programs for interface control of smart secondary system. Nine subjects were involved in the study for measuring operation time of secondary controls. Results: When the driver was in the stationary condition, the average operation time of smart secondary devices decreased 32.5% in the normal subjects (p <0.01), 47.4% in the subjects with left hemiplegic disabilities (p <0.01) and 38.8% in the subjects with right hemiplegic disabilities (p <0.01) compared with conventional secondary devices. When the driver was driving for the test in the simulator, the average operation time of smart secondary devices decreased 36.1% in the normal subjects (p <0.01), 41.7% in the subjects with left hemiplegic disabilities (p <0.01) and 34.1% in the subjects with right hemiplegic disabilities (p <0.01) compared with conventional secondary devices. Conclusion: The smart secondary devices using iPad for people with hemiplegic disabilities showed significant reduction of operation time compared with conventional secondary controls. Application: This study can be used to design secondary controls for adaptive vehicles and to improve the quality of life of the people with disabilities.

• The Journal of Advanced Prosthodontics
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• v.7 no.1
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• pp.51-55
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• 2015

PURPOSE. Bone density at implant placement site is a key factor to obtain the primary stability of the fixture, which, in turn, is a prognostic factor for osseointegration and long-term success of an implant supported rehabilitation. Recently, an implant motor with a bone density measurement probe has been introduced. The aim of the present study was to test the objectiveness of the bone densities registered by the implant motor regardless of the operator performing them. MATERIALS AND METHODS. A total of 3704 bone density measurements, performed by means of the implant motor, were registered by 39 operators at different implant sites during routine activity. Bone density measurements were grouped according to their distribution across the jaws. Specifically, four different areas were distinguished: a pre-antral (between teeth from first right maxillary premolar to first left maxillary premolar) and a sub-antral (more distally) zone in the maxilla, and an interforaminal (between and including teeth from first left mandibular premolar to first right mandibular premolar) and a retroforaminal (more distally) zone in the lower one. A statistical comparison was performed to check the inter-operators variability of the collected data. RESULTS. The device produced consistent and operator-independent bone density values at each tooth position, showing a reliable bone-density measurement. CONCLUSION. The implant motor demonstrated to be a helpful tool to properly plan implant placement and loading irrespective of the operator using it.

• Journal of the Ergonomics Society of Korea
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• v.33 no.5
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• pp.313-321
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• 2014

Objective: The purpose of this study is to develop products that prevent muscular skeletal disease of farm workers, which would bring improvement for an efficient harvesting work. Background: A pretest for product development and a survey research was carried out to inspect the problems of current harvesting work procedure. The product was developed and assessed based on ideas to supplement and improve these weak points. Method: A total of twenty men were recruited to evaluate the effects of harvest baskets on the upper-limb muscle activity, working hours. For the usability evaluation, electromyogram and working hours of previous working method (disuse of harvest basket, one-hand carriage of the basket) and new working method with the usage of newly-developed harvest basket was examined. The whole anterior deltoid, biceps brachii and erector spinae on both sides, which make a total of six muscle parts, were used for this experiment. The results were analyzed using ANOVA with muscle activity (%MVC) of each three forms of work and required work time from SPSS 18.0. Results: According to the test result, all muscles did not demonstrate any statistically significant difference, with an exception of the backbone erector (right). The muscle activity of backbone erector (right) in the work method that uses the harvest basket developed in this study was detected to be approximately 23% less than that of the previous working method. Moreover, compared to the previous working method, the required work time decreased to a statistically significant degree. Conclusion: As such, the decrease in the amount of waist muscle usage at harvesting work would enable the prevention of muscular skeletal disease and stabilization of lumbar spine. Application: Which in turn would increase the effectiveness and reduce personnel expense (labor costs) while enhancing productivity with a decreased working hours.

• Journal of the Korean Home Economics Association
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• v.28 no.2
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• pp.91-106
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• 1990

This study focuses on consumers' advertising discriminatory competencies and the influencing facors. So the objects of this study are as follows : 1) to identify the overall level of advertising discriminatory competencies. 2) to examine if consumer attitude variables have significant effects on the ads. discriminatory competenceis. 3) to examine if the frequencies of contacting advertising variable have significant effects on the ads. discriminatory competencies. 4) to examine if socio-economics variables-age, educational level, monthly family income, occupational status-have significant effects on the ads. discriminatory competencies. 5) to find out the independent influence of variables related to the ads. discriminatory competencies. For this purpose, a survey was conducted using questionaires and advertisement papers. The data used in this study included 194 Homemakers living in Seoul. The ads. used in this study included ads. of diary products like foods, drinks, medicine, cosmetic, detergent in TV, radio, newspaper and magagine. Statistics were Frequency Distribution, Mean, percentile, ANOVA, Scheff -test, Pearsons' Correlation, Multiple Regrassion Analysis. Major findings were as follows : First, in 26 items(70%) of 37 items measured consumers' ads. discriminatory competencies, the rate of right answer was below 50%, so over the half of consumers were misleaded by the deceptive ads. Second, consumers' ads. discriminatory competencies differed significantly according to consumer attitude variables but no according to the frequency of contacting advertising. Third, according to socio-demographic variables-age, educational level, monthly family income, occupational status-advertising discriminatory competencies differed significantly. In group of lower age, higher educational level, higher income and professional occupation status, the level of ads. discriminatory competencies were high. Forth, the most influencing variabel on ads. disciriminatory competencies were eudcational level and in turn general attitude toward ads., attitude toward consumerism. This three variables explain 22.9% of dependent variable's variance. From these findings, the following suggestions are made, First, the consumer education offering informations and learing practical ads. discriminatory competencies should be conducted for all consumers wheather they are educated or not. Also the education to improve the consumer attitude must be. Second, considering misleading level, the business must make the regulatory standards and reinforce the regulation voluntarily, and by enforcing the regulation of ads. and deciding more diverse, objective and exact standards, the government should keep the consumer's right to know.

• Journal of Sensor Science and Technology
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• v.23 no.2
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• pp.114-121
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• 2014

We report a polysilicon active area membrane field effect transistor (PSAFET) pressure sensor for low stress deflection of membrane. The PSAFET was produced in conventional FET semiconductor fabrication and backside wet etching. The PSAFET located at the front side measured pressure change using 300 nm thin-nitride membrane when a membrane was slightly strained by the small deflection of membrane shape from backside with any physical force. The PSAFET showed high sensitivity around threshold voltage, because threshold voltage variation was composed of fractional function form in sensitivity equation of current variation. When gate voltage was biased close to threshold voltage, a fractional function form had infinite value at $V_{tn}$, which increased the current variation of sensitivity. Threshold voltage effect was dominant right after the PSAFET was turned on. Narrow transistor channel established by small current flow was choked because electron could barely cross drain-source electrodes. When gate voltage was far from threshold voltage, threshold voltage effect converged to zero in fractional form of threshold voltage variations and drain current change was mostly determined by mobility changes. As the PSAFET fabrication was compatible with a polysilicon FET in CMOS fabrication, it could be adapted in low pressure sensor and bio molecular sensor.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.43-80
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• 2008

The purpose of this research is to analysis the swing of driver used by professional golfers during on-season. In order to collect on-season driver swings of research objects, which are three KPGA(Korean Professional Golfer Association) professional golfers, measurements were carried out right after the last game of a season. The analysis range was set to down-swing point while analysis was conducted to after-impact, release point. As a result, systematic process between leading segments of the previous precise kinematic analysis research seems to turn up the same. However, there were different results compared to the preceding research. All three testers expressed adduction of left hand which could not be described with forming cocking angle, in consequence, adduction of left hand does not have a big effect on formation of cocking. Moreover, chest movement right before the impact; which was emphasized in previous research, the direction was not opposite but the same with the ball.

• Journal of Biosystems Engineering
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• v.43 no.4
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• pp.273-284
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• 2018

Purpose: Conventional headland turning typically requires repeated forward and backward movements to move the farming equipment to the next row. This research focuses on developing an upland agricultural robot with an optimized headland turning mechanism that enables a $180^{\circ}$ turning positioning to the next row in one steering motion designed for a two-wheel steering, four-wheel drive agricultural robot named the HADA-bot. The proposed steering mechanism allows for faster turnings at each headland compared to those of the conventional steering system. Methods: The HADA-bot was designed with 1.7-m wide wheel tracks to travel along the furrows of a garlic bed, and a look-ahead path following algorithm was applied using a real-time kinematic global positioning system signal. Pivot turning tests focused primarily on accuracy regarding the turning radius for the next path matching, saving headland turning time, area, and effort. Results: Several test cases were performed by evaluating right and left turns on two different surfaces: concrete and soil, at three speeds: 1, 2, and 3 km/h. From the left and right side pivot turning results, the percentage of lateral deviation is within the acceptable range of 10% even on the soil surface. This U-turn scheme reduces 67% and 54% of the headland turning time, and 36% and 32% of the required headland area compared to a 50 hp tractor (ISEKI, TA5240, Ehime, Japan) and a riding-type cultivator (CFM-1200, Asia Technology, Deagu, Rep. Korea), respectively. Conclusion: The pivot turning trajectory on both soil and concrete surfaces achieved similar results within the typical operating speed range. Overall, these results prove that the pivot turning mechanism is suitable for improving conventional headland turning by reducing both turning radius and turning time.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.19-26
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• 2014

This study investigated foot pressure patterns between experienced skiers and intermediate skiers during alpine skiing. Five experienced skiers and five intermediate skiers participated in this study. Foot pressure measurement system was used to measure vertical ground reaction force (vGRF) and contact area under the six plantar regions. Each participant was asked to perform basic parallel turns and carved turns on a $18^{\circ}$ groomed slope. Each right turn was divided into the initiation phase, the steering phase 1 and 2. For the initiation phase of the basic parallel turns, significantly greater contact area was found on the LRF and RRF of the intermediate skiers (p<.05) and significantly greater vGRF was found on the LRF of the intermediate skiers (p<.05). Also significantly greater vGRF and contact area were found on the LRF and RRF of the intermediate skiers at the steering phase 1 (p<.05) and on the LRF of the intermediate skiers at the steering phase 2 (p<.05). For the carved turns, significantly greater vGRF and contact area were found on the LRF and RRF of the intermediate skiers at all three phase (p<.05). On the other hand, significantly greater vGRF was found on the RFF of the experienced skiers at the steering phase 1 (p<.05). Also significantly greater vGRF and contact area were found on the RMF of the experienced skiers at the steering phase 2 (p<.05). In order to increase performance, we suggest that the intermediate skiers should be unweighted at the initiation phase and shift the body weight to the forefoot of the outer foot at the steering phase 1. Also, the outer ski should be loaded more than the both skis at the steering phase 1 and 2.

• Journal of Korean Society of Transportation
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• v.34 no.4
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• pp.291-303
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• 2016

The number of traffic accidents at intersections has been increased over the past decade, and in 2014, accounted for 44% of the total traffic accidents. In addition, since most of road accident black spots include signalized intersections, the improvement of safety on signalized intersection is top priority for national road safety program in Korea. For the decision of most effective action plan for the safety of signalized intersection, this study conducted meta-analyses to assess the effects of various road safety facilities at signalized intersection on traffic accidents. We selected 19 articles regarding the prediction of traffic accidents at signalized intersection and calculated 34 individual effect sizes on 8 variables included in the articles. The results found that there was a statistically significant negative relationship between the occurrence of traffic accident and the presence of all of road safety facilities except an exclusive left turn bay. It shows that most of the road safety facilities could prevent traffic accidents, and intersection channelization has the most effective on the reduction of traffic accidents followed by left-turn acceleration lane, lightning, crosswalk, exclusive right-turn lane and median barrier.

• Journal of the Korean Institute of Gas
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• v.25 no.5
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• pp.78-87
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• 2021

This paper analyzes the range and attributes of the traffic information service between domestic public institutions and private companies, and suggests the possibility of joint application of node-link information for each company and the possibility of joint use of private traffic information. For this purpose, the present condition and attributes of domestic and foreign traffic information node-links (link length, node ID number, U-turn information, lane information, left turn information, right turn information, etc.) were analyzed. The analysis targets, the node-link of the national standard node and the two companies were analyzed. The area of the experiment was selected in Jongno-gu, Seoul, where standard-link information is complex, traffic volume is high, and various standard-links exist. The experiment was conducted by comparing and analyzing the traffic information attributes of three types of node-links and performing node-links overlapping matching (utilizing encoding_decoding method), and the possibility of matching node-links and attributes of different specifications was analyzed using Open LR technique.