• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.17 no.4
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• pp.255-265
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• 2024

To address environmental challenges and improve energy efficiency, the adoption of electric vehicles has led to a surge in related research. However, to comprehensively understand the research trends within the field of electric vehicles, it is necessary to systematically analyze vast amounts of data. This study systematically analyzed research trends in the field of electric vehicles and identified key research topics through LDA topic modeling, based on 36,519 papers related to electric vehicles collected from the SCIE database. The data analysis revealed a total of 10 major topics, of which three were identified as hot topics showing an upward trend: Electric Vehicle Charging Infrastructure, Energy and Environmental Policy, and Optimization and Algorithms. Conversely, five topics were identified as cold topics exhibiting a downward trend: Battery Temperature and Cooling, Battery Materials and Chemistry, Motor and Mechanical Design, Control Strategies and Systems, and Battery Components and Materials. This study provides basic data for understanding the current research trends in electric vehicles and offers valuable information for researchers in selecting research topics related to electric vehicles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5305-5310
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• 2012

This study is Carpal tunnel syndrome(CTS) disorder of median nerve at wrist. It is usually diagnosed through clinical manifestation and Nerve Conduction Study(NCS). NCS of the median nerve before and after operation were compared in twenty four patient's with CTS, in order to seventeen patient's evaluate the prognostic value of that findings. Analysis result symptom profile of CTS in total number of patient's 17 (Female:17, Male:0), 21 hands (Rt:9, Lt:4, Both:4), Ages(31~60), Mean duration of symptom months($46.6{\pm}36.1$), Mean interval between 1st and 2nd NCS months($20.5{\pm}7.1$), Sensory symptoms(Tingling:21, Numbness:19, Noctunal paresthesia:17), Motor symptoms(Thenar atrophy:20, Trigger finger:2, Morning stiffness:3), Post-operative symptoms(Free:38.1%, >50% improve:52.4%, <50% improve:9.5%). NCS was normal range after operation than before in Sensory nerve conduction study 4 patients's and Motor nerve conduction study 5 patients. Surgery before and after Sensory nerve action potential (SNAP) responses showed improvement over the previous results. Forward by the patient's occupation and occupation patterns of CTS, other treatment methods and surgical treatment of CTS by comparing the degree of improvement to identify and correct nerve conduction study to judge whether the patient's operation.

• Science of Emotion and Sensibility
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• v.14 no.3
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• pp.395-402
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• 2011

As the consumer market for odor products grows, companies producing healthcare products are beginning to pay more attention to the emotional aspect of an odor product in order to differentiate their products from competitors. In the following research, the affective effect of odor product was investigated while focusing on relaxation and working contexts using orange and pine scents, since these are typical odors in current domestic market. Two empirical studies were carried out. First, in experiment I, 18 subjects, all of whom were university students, spent 20 minutes sitting comfortably on a sofa while electrocardiogram assessments were made. After a five-minute break, in experiment II, the same subjects were provided with both arithmetic and geometric questions and their electroencephalogram readings was recorded from eight channels. All subjects participated in three sessions - no odor, an orange scent, and then a pine scent - with a minimum time interval of 24 hours. The results show that in the context of a pine scent, both the activation ratio of subjects' parasympathetic system and those of the Sensory Motor Rhythm waves and Mid Beta waves were at the highest peak. Therefore, the pine scent helped the subjects to feel more comfortable and more focused at the same time. In other words, it gave them a state of meditated attention. In addition, it was found that the right brain was activated twice the intensity when the subjects worked through the geometric questions, whereas both sides of the brain were activated in equal magnitude during the process of arithmetic tasks. This replicates previous studies of the functional aspect of the right brain - being responsible for spatial and creative thinking.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5715-5721
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• 2011

This research analyzed the cognitive factors affecting stroke patient's activity of daily living performance and suggests the approaches which can contribute to the effective activity of daily living performance in the rehabilitation treatment of stroke patients. In this study, Seoul Computerized NeuroCognitive Function Test (SCNT) and MBI have been performed for 21 patients under extensive rehabilitation treatments, hospitalized in the rehabilitation clinic of A hospital after being diagnosed as a stroke caused by cerebrovascular disorders. To assess the effectiveness of the cognitive factors which affect the stroke patient's activity of daily living performance, activity of daily living performance values were set as dependent variables and 10 cognitive factors were included in the model to carry out analysis of the multiple regression analysis. The results show that stroke patient's activity of daily living performance have statistically significant correlations with divided attention, motor control and selectivir attention. In addition, cognitive factors explained 69.8% of the stroke patient's activity of daily living performance. Consequently, if divided attention and motor control are considered as a focal point of training in the rehabilitation treatment of stroke patients, we can effectively promote the improvement of the activity of daily living performanceroutine activities.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.1
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• pp.1-23
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• 1998

Work-related Low Back Pain(LBP) is one of tile most important Issues in the field of industrial safety and health. Particularly, manual lifting is known as a major cause of work-related LBP and impairment. Total number of 163 manual lifting tasks in motor assembly processes were investigated. The 1981 and the 1994 equations developed by National Institute for Occupational Safety and Health(NIOSH) were applied to evaluate potential hazards of lifting-related LBP. Comparisons between the 19R I and 1994 NIOSH criteria were made. The relationships between the NIOSH criteria and lifting-related LBP were also analyzed. The results of this study are as follows: 1. The values of Action Limit(AL) by the NIOSH 1981 lifting equation. Recommended Weight Limit(RWL) by the 1994 equation and the weight of the load handled at each manual lifting task were shown log-normal distributions. 2. LI'(the weight of tile load/AL) and LI(the weight of the load/RWL) were calculated estimate the physical stress imposed by each individual lifting task. As a result. 76.7% of the total LI' value exceeded 1 and 12.9% exceeded 3, and 84.7% of the total LI values exceeded 1 and 20.9% exceeded 3. 3. Bus 2 Department showed the highest rate of LI'>1 and LI>1 and Bus 1 Department showed the highest rate of LI'>3 and LI>3 4. In general, the RWLs by the 1994 equation were found lower than the ALs by the 1981 equation. It is assumed to he resulted from the fact that the 1994 equation includes methods evaluating asymmetrical lifting tasks and lifts of objects with less then optimal hand-container couplings, and also covers a larger range of work durations and lifting frequencies than the 1981 equation. 5. Significant correlations were found between LI' and incidence of LBP (R=0.734, p<0.05). LI and incidence of LBP(R=0.671. p<0.10) and load-weights and incidence of LBP(R=0.797, p<0.05). 6. Control measures are required to achieve the value of LI less than 1 for some tasks having high LI values. Engineering control is highly recommended for some tasks having the value of LI above 3.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.69-75
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• 2019

The cooling performance of heat pump system for light-duty commercial electric vehicle was evaluated experimentally. The cooling performance characteristics of the heat pump for light-duty commercial electric vehicles were evaluated by varying the temperature, flow rate of chiller coolant, and electric compressor speed, under the exterior air temperature of 35 ℃ and interior air temperature of 25 ℃. Increasing the compressor speeds decreased the cooling system efficiency by 16.4 % on average with the cooling capacity increasing by 8.0 % on average and the compressor work increasing by 27% on average. To use waste heat from the coolant to chill power electronic components, such as the motor and inverter, a chiller was installed to transfer heat between the coolant and refrigerant. Increasing the temperature of the chiller coolant from 35 ℃ to 55 ℃ decreased the efficiency by 18.2 % on average due to higher condensing heat source. Increasing the coolant flow rate from 10 liter/min to 20 liter/min did not affect the cooling capacity of the system due to a similar total condensing heat transfer rate at the chiller and the exterior heat exchanger. In future works, heating performance will be investigated by varying the operating conditions to use the chiller's waste heat with an improvement of heating capacity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.237-246
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• 2019

The Electro-Mechanical Brake (EMB) is the next generation braking system for automobiles and railway vehicles. Current brake systems for high-speed trains generate a braking force using a pneumatic cylinder, but EMB systems produce that force through a combination of an electric motor and a gear. In this study, an EMB operation mechanism capable of generating a high braking force was proposed, and structural and vibration analyses of the gears and shafts, which are the core parts of the mechanisms, were performed. Dynamic structural analysis confirmed that the maximum stress in the analysis model was within the yield strength of the material. In addition, the design that maximizes the diameter of the motor shaft was found to be advantageous in strength, and large shear stress could be generated in the bolt fixing the gear and eccentric shaft. In addition, a test apparatus that can reproduce the mechanism of the analytical model was fabricated to measure the strain of the fixed bolt part, which is the most vulnerable part. The strain measurement results showed that the error between the analysis and measurement was within 10%, which could verify the accuracy of the analytical model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5132-5142
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• 2015

The purpose of this study was to find effect of upper extremities exercises using two different supporting surface, mobile surface and fixed surface in sitting on the function of upper extremities for the patients with stroke. The study period was between July 5, 2012 and August 1 2012. The subjects were 20 subjects who were randomly divided into two groups : (1) mobile surface group, (2) fixed surface group. The mobile surface group performed bilateral upper extremities exercise sitting on balance disc, and the fixed surface group was provided fixed surface chair. Both groups performed 30 minutes 5 times per a week for 4weeks. The Manual Functional Test(MFT) and Fugl-Meyer Motor Function Assessment(FMA) was used to measure the differences of upper extremity functions before and after interventions. The results of this study were as follows. First, Both groups, mobile surface group and fixed surface group showed the significant increase(p<.05) in upper extremity function. Second, the improvements of the hand function in mobile surface group showed significant difference comparing with the group with fixed surface. Therefore, the results of this study showed the bilateral hand exercise program on mobile surface is more effective than the fixed surface bilateral hand exercise program for the patients with stroke.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.2925-2930
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• 2011

A vehicle fuel economy is very important issue in the view of fuel cost and environmental regulation. The fuel economy is much improved according to the development of electric, electronic and mechanical technology, but up to now the measurement of it tests the given mode(LA-4, FTP-75, etc) within computer simulation program and engine dynamometer. This fuel economy is different with it of real road. The one of main reason is not considered the gradient of the road. To estimate the effects of fuel economy at highway with gradient in this paper, we measure the amount of fuel consumption and calculate the fuel economy of it with running the Youngdong highway with high gradient. Also this paper analysis and compares the fuel economy with gradient and without gradient when the vehicle runs the same driveway. Then we calculate the total energy created the difference of fuel consumption amount of the two cases and calculate the consumpted energy by tire driving force from the torque and power of engine in the simulation. This paper verifies the relation of the driving force and the total energy by creating the difference of fuel consumption amount. This paper also proposes the method of fuel economy improvement despite of gradient at the result.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.351-358
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• 2016

An Electrical Point Machine (NS:New-type Switch), which is equipped and operated at railways in Korea, has been used since the 1960s after being imported from Japan. On the other hand, although the mechanical configuration has improved the position motor control circuit, the electrical connection has not been improved, so NS may have a problem, such as the interlocking system of automatic train operation. In addition, NS is the most vulnerable part in the railway system and a huge train accident may occur due to minor defects. The existing NS wiring set of the circuit controller should be checked only if fixed. Therefore, an excessive inspection time only by a Railroad Signal expert is required. In this paper, the improvement of electrical connection in a NS wiring set, such as the position motor control circuit, was developed and the prototype was installed at Seoul Metro in the distance to go section. The results can be used to help make appropriate adjustments. The improvement of the NS wiring set enhance the maintenance efficiency, passenger service and the stability of the signal system as well as reducing the maintenance cost.