• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.278-282
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• 2001

The purpose of this study is to introduce a new spacer damper for the bundle transmission lines network. It has the special design, the main characteristics and advantage of this new kind of spacer damper. An Existing spacer damper with bolted clamps, although widely used, is a method of connection with certain disadvantage both as regards assembly on the conductor and in the course of time. Even if tightening torque is correctly applied by using bolt with share head or torque wrench during working time, the aeolian vibration could involve untightening during life time, so the cable can move into the Jaws and wire's breakage appear. To salve this problems, France, Japan and other countries had developed a spacer damper with an automatic system through many years. This new spacer damper is an original automatic clamping device (beltless) which does not require special tool for its installation. This device prevents clamp unlocking problems, ensures a simple installation and ensures a reliable-tightening during life time. Therefore, it is necessary to localize this boltless spacer damper with automate clamping device.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.4
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• pp.81-87
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• 2016

Recently, as the heterogeneous network (HetNet) has been deployed widely to support various kinds of Radio Access Networks(RANs) with a combination of Macro, Pico, and/or Femto cells, research and standardization efforts have been very active regarding the concept of Licensed Shared Access (LSA) for supporting spectrum sharing. In order for a mobile device to efficiently support the spectrum sharing, the mobile device shall be reconfigurable, meaning that its radio application code has to be adaptively changed in accordance with the hopping of desired spectral band. Especially, Working Group 2 (WG2) of Technical Committee (TC) Reconfigurable Radio System (RRS) of European Telecommunications Standards Institute (ETSI) has been a main driving force for developing standard architecture for Multi-mode Mobile Device (MD) that can be applied to the LSA system. In this paper, we introduce the Multi-mode MD architecture for supporting LSA-based spectrum sharing. An implementation of a test-bed of Multi-mode MD is presented in order to verify the feasibility of the standard MD architecture for the purpose of LSA-based spectrum sharing through various experimental tests.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.458-468
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• 1996

The Oil Palm industry has developed tremendously with the increasing of planted area from 54,000 hectaresin 1960 to about 2.28 million hectares in 1995. This is expected to increase further to 2.5 million hectares by the year 2000. However, there has been an increasing difficulty in obtaining sufficient labour for the oil palm plantations. At present , harvesting of oil palm fresh fruit is facing an acute shortage of workforce as the workers are much more attracted to the better working environment and salary in the industrial sector. Harvesting of short palm is easily done by using a chisel attached to a short steel pole. Cutting is done by moving the tool at high speed to the target. The weight of the tool coupled with the speed of throwing will produce enough energy to cut the bunch stalk. In this cutting method, sharpness of the cutting device, weight of tool and the speed of throwing contribute to the efficiency of the tool . For the tall palms, a sickle attached to a ong pole is used and the job is more difficult compared to the short palms. Lifting of pole and cutting jobs require great effort and skills. This paper describes the basic design needs in developing an appropriate device that is practical for field use. A prototype design was developed and tested.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.265-271
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• 1998

In the hydrologic and hydrochemical studies of natural waters, oxygen and hydrogen isotope compositions of waters are very important to elucidate the origin and circulation pattern of water in the hydrologic system. The hydrogen isotope analysis of waters usually has been undertaken through the reduction of water to form hydrogen gas using pure metals (in general, zinc and uranium). In 1996, a new apparatus (H/Device) was developed to prepare the water samples (by the reduction with Cr metal) without some intrinsic problems that may yield incorrect and/or inaccurate data, and was installed at 1997 in the Center for Mineral Resources Research (CMR) in Korea University. However, the optimistic conditions of preparation and analysis of samples has not been established. In this paper, we introduce the efficiency of H/Device to obtain accurate hydrogen isotope values of water, and discuss both the optimum conditions including the effective reduction time and the probable mixing (memory) effect between successive samples. We obtained large amounts of a laboratory working standard (KUW; Korea University Water) with the average ${\delta}D_{SMOW}$ value of $-42.1{\pm}1.0$‰ $(1{\sigma})$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1521-1527
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• 2013

This study proposes a wearable master device that can measure the joint stiffness and the angular displacement of a human operator to enhance the adapting capability of a slave system. A lightweight inertial sensor and the exoskeleton mechanism of the master device can make an operator feel comfortable, and artificial pneumatic muscles having a working principle similar to that of human muscles improve the performance of the slave device on emulating what a human operator does. Experimental results revealed that the proposed master/slave system based on the muscle stiffness sensor yielded uniform tracking performance compared with a conventional position-feedback controller when the payload applied to the slave system changed.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.2
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• pp.37-44
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• 2019

The primary objective of this study is to develop a prototype of all-in-one attachment-based PHC pile head cutting robot that improves the conventional work in safety, productivity, and quality. For this, the following research works are conducted sequentially; 1)literature review, 2)development of an all-in-one attachment-based PHC pile head cutting robot prototype, 3)performance evaluation of each device, 4)economic analysis of an automated method. As a result, PHC pile cutting level sensing device, PHC pile cutting device, PHC pile handling device are developed. Futhermore, working process of an automated method is developed based on result of performance evaluation. According to the economic analysis result, the cost of the automated method was 21.37% less than that of the conventional method, and the economic efficiency was also superior(ROR 215.44%, Break-even Point 5.52month). It is expected that conclusions for future improvements are used in the development of the all-in-one attachment-based PHC pile head cutting robot to practical use.

• Journal of Drive and Control
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• v.19 no.4
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• pp.97-103
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• 2022

Low fertility rates and increased life expectancy further exacerbate the process of an aging society. This is also reflected in the gradual increase in the proportion of vulnerable groups in the social population. The demand for improved mobility among vulnerable groups such as the elderly or the disabled has greatly driven the growth of the electric-assisted mobility device market. However, such mobile devices generally require a certain operating capability, which limits the range of vulnerable groups who can use the device and increases the cost of learning. Therefore, autonomous driving technology needs to be introduced to make mobility easier for a wider range of vulnerable groups to meet their needs of work and leisure in different environments. This study uses mini PC Odyssey, Velodyne Lidar VLP-16, electronic device and Linux-based ROS program to realize the functions of working environment recognition, simultaneous localization, map generation and navigation of electric powered mobile devices for vulnerable groups. This autonomous driving mobility device is expected to be of great help to the vulnerable who lack the immediate response in dangerous situations.

• Journal of Biosystems Engineering
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• v.39 no.4
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• pp.253-260
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• 2014

Purpose: This study investigated the harvesting properties of the giant miscanthus (Miscanthus ${\times}$ giganteus) to measure the required mowing power for different stem conditioning methods in order to shorten the drying time after mowing and the bale density so that the crop can be used as biomass in the winter season. Methods: The required mowing power and bale density were measured using a power measurement device, three different mower-conditioners, and a mid-sized round baler under different working speeds and conditioning methods. Results: For the various mower-conditioners, the average stem length from mowing was 0.86-0.91 m, and the available working speed was 1.6 m/s. The steel roller-type mower-conditioner showed better stem conditioning but could not mow over a working speed of 1.6 m/s. The required average power of the mower-conditioners varied from 23.8 kW for the steel roller-type rotary disk mower-conditioner with a working width of 2.4 m to 37.2 kW for the flail-type rotary disk mower-conditioner with a working width of 3.2 m at a working speed of 1.6 m/s. The bale densities were $155.8-172.2kg/m^3$. The highest bale density was measured for stems with no conditioning and a moisture content of 11.3% (d.b.) mowed by the rotary disk mower. The bale density was affected by the mowing method because of the low moisture content of the miscanthus stems. Conclusions: In terms of the working performance and conditioning statue, the steel roller-type mower-conditioner is a better choice at a working width of 2.4 m, while the flail finger-type mower-conditioner is better at a working width of 3.2 m. The type of mower-conditioner used for giant miscanthus harvesting should be determined by considering the harvest area, workable period, and working performance of a mower-conditioner and baler during the winter.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.28 no.2
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• pp.106-114
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• 2017

Objectives: This study was to examine the effectiveness of computerized cognitive ability enhancement program (CCAEP) using Smarttoy. The CCAEP using Smart-toy which can interact with children via bluetooth is a kids-friendly and convenient method for improving children's cognitive abilities by increasing their motivation for performing the program. We developed the CCAEP which designed to train auditory-verbal memory, visual-spatial memory, auditory-verbal working memory, and visual-spatial working memory. Methods: Eighteen children aged 8 to 10 participated in CCAEP individual training composed of 8 sessions of 40 minutes each for 4 weeks. The effect of the training was measured with Smart Toyweb's cognitive assessment tasks (smart device based assessment) as well as traditional neuropsychological tests before and after the training. Results: Children showed significant improvement in auditory-verbal memory, visual-spatial memory, auditory-verbal working memory and visual-spatial working memory abilities after the training. Conclusion: This study demonstrated promising results suggesting the effectiveness of CCAEP using Smart-Toy in clinical settings as well as school and home situations. Further controlled study with larger sample size including various clinical groups is needed to confirm the present results.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.1
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• pp.105-115
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• 2020

With the decrease of the agricultural population in Korea, the workers who is vulnerable to labor are increasing in agricultural industry because of aging, feminization of population. They are exposed in poor working environment with higher temperature and concentrations of dust, gas. Higher concentration of harmful gas and dust can cause chronic and acute disease to workers depending on exposure intensity and frequency. In order to improve the working environment in the livestock facilities, It is important to secure monitoring data of the thermal environment and the concentration of harmful gases and fine dust. Multi-point measurement was performed to analyze the regional environmental conditions in the pig rooms. When analyzing the working environment, video monitoring was conducted to analyze the concentration changes of ammonia, hydrogen sulfide and fine dust according to worker movement and work type. Ammonia and hydrogen sulfide monitoring result showed 1.5~2 times higher concentrations than other work when working in the pigs living zone, and 2~4 times higher than other work when working to increase the activity of pigs. In the case of fine dust, the result was 1.3 times higher than the worker's exposure standard in a specific work. The concentrations of gases and dusts from pig farms are not of concern for acute poisoning in normal work, but there is a risk of chronic respiratory disease if they are continuously exposed. Accordingly, there is a need for development of work environment monitoring device tailored to workers and preparation of alternatives.