• Korean Journal of Construction Engineering and Management
• /
• v.19 no.2
• /
• pp.117-125
• /
• 2018

The primary objectives of this study are to develop a detail design of automated PHC pile head cutting machine and structural stability analysis of detail design that improves the conventional head cutting work in safety, quality, and productivity. For this, the following research works are conducted sequentially; 1)literature review and field study, 2)expert survey and interview, 3)selection of core technology using AHP analysis, 4)deduction of detail design 5) verification of structural stability. As an outcome, it is analyzed that gripper and gripper bearing shaft are structurally stable. Their maximum stresses are shown as 15.93%, 10.58% compared to their yield strength respectively. The results of detail design and structural stability analysis in this study will be utilized for the actual development of the automated PHC pile cutting machine prototype.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.5
• /
• pp.215-222
• /
• 2018

Recently, various motion beds have been actively developed and popularized. The motion bed has the functions of height adjustment, back plate rising, knee lifting, tilt function and left / right rotation, and the remote control can conveniently be used by the patient himself or the caregiver to move the patient. However, since the medical bed for use does not have a function of preventing pressure ulcers, exchanging sheets, and transferring patients, it is necessary to disperse body pressure by using a pressure ulcer prevention matrix to prevent pressure ulcers. However, it is accompanied by muscle strength and hard work, and nurses are avoiding difficult nursing care. In this study, we developed the first prototype in the world and confirmed that the system works normally with the goal of developing multifunctional beds that automatically perform the prevention of bed sores, the exchange of sheets and the transfer of patients in order to facilitate such nursing work. It is anticipated that the proposed multifunctional motorized bed in the future will be a model of a medical robot for smart healthcare.

• Journal of Agricultural Extension & Community Development
• /
• v.20 no.2
• /
• pp.451-484
• /
• 2013

This study investigated the factors that influence subjective well-being of immigrant wives in Korea. We initially grouped the factors into 3 categories: personal, domestic, and social. For personal factors, we included couple's age difference, reason for entry, religion, marital duration, employment status, economical status, acculturation to Korean culture, acquisition of Korean language, and ego-resiliency. For domestic factors we included marriage process, reason for marriage, husbands' understanding of wife's native language, husbands' understanding of wife's culture, marital satisfaction, existence of children, head of the household, and parenting efficacy. Finally for social factors, awareness of welfare services and systems, use of public institutions and civil organizations, and participation in social groups were included. We recruited 256 immigrant wives who live in Asan City, Chungnam Province and the data were analyzed by multiple linear regression. The factors that statistically significant were: ego-resiliency, marital duration, acculturation to Korean culture and economic status among personal factors; parenting efficacy, marital satisfaction and marriage process (married without a matchmaker) among domestic factors; participation in self-help group of women from the same mother country, awareness of welfare services and systems, participation in hobby club, and participation in fraternal/religious society among social factors. It is hoped that this paper will yield general insights into subjective well-being of immigrant wives and may help them to develop inner talent and strength.

• Journal of the Korean Academy of Esthetic Dentistry
• /
• v.25 no.2
• /
• pp.98-108
• /
• 2016

In recent days, perhaps the biggest driver in new material development is the desire to improve restorations esthetics compared to the traditional metal substructure based ceramics or all-ceramic restorations. Each material type performs differently regarding strength, toughness, effectiveness of machining and the final preparation of the material prior to placement. For example, glass ceramics are typically weaker materials which limits its use to single-unit restorations. On the other hand, zirconia has a high fracture toughness which enables multi-unit restorations. This material requires a long time sintering procedure which excludes its use for fast chair side production. Hybrid ceramic material developed for CAD/CAM system is contained improved nano ceramic elements. This new material, called a Resin Nano Hybrid Ceramic is unique in durability of function and aesthetic base compositions. The new nano-hybrid ceramic material is not a composite resin. It is also not a pure ceramic. The material is a mixture of both and consists of nano-ceramic fillers. Like a composite, the material is not brittle and is fracture resistant. Like a glass ceramic, the material has excellent polish retention for lasting esthetics. The material is easily machined by chair side or in a dental lab side, could be an useful restorative option.

• Journal of the Korea Concrete Institute
• /
• v.16 no.2 s.80
• /
• pp.221-228
• /
• 2004

In recent years building floors become larger and more spacious due to the development of new design methods and high strength and light weight materials. However, such long span floor systems may provide smaller amount of damping and have a longer period so that they may be more vulnerable to the floor vertical vibration. In Korea when floors are to be checked against the floor vertical vibration, the provisions developed in foreign countries have been used. However these guidelines have been developed based on human perception, which may vary from country to country. Also, Korea have particular floor systems, such as flat plate floor system of apartment building. This study attempts to evaluate the vibration performance of the floors in typical apartment buildings. Two different floors with the area of $28 m^2$ and $32 m^2$ were investigated. The criteria provided by ATC-1(1999), AISC-11(1997), AIJ(1991) and the local criteria developed in the previous study(Han, 2003) was used to check the acceptability of the floor vertical vibration.

• Journal of the Korea Concrete Institute
• /
• v.18 no.6 s.96
• /
• pp.769-776
• /
• 2006

Recently, owing to the development of industry and the improvement of building techniques, concrete structures are becoming larger and higher. In hardening of these large connote structures, the heat of hydration gives rise to considerable thermal stress depending on the size and environmental condition of concrete, which might cause thermal cracking. Especially, the crack may cause severe damage to the safety and the durability of concrete structure. This study investigates the thermal properties of concrete according to several binder conditions, such as OPC, Belite rich cement(BRC), slag cement(SC), blast furnace slag(B) added cement fly ash(F) added cement and blast-furnace-slag and fly ash added cement. As a result of this study, the properly of concrete is most better BRC than others, and fly ash(25%) added cement and BFS(35%)-fly ash(15%) added cement gets superior effect in the control of heat hydration. But synthetically considered properties of concrete, workablity, strength heat hydration, etc, it is more effective to use mineral admixture. Especially, to be used Blast Furnace slag is more effective.

• Journal of the Korea Concrete Institute
• /
• v.19 no.4
• /
• pp.411-420
• /
• 2007

The applicability of headed bars in exterior beam-column joints under reversed cyclic loading was investigated. A total of ten pullout tests were first performed to examine pullout behavior of headed bars subjected to monotonic and cyclic loading with test variables such as connection type between head and bar stem (weld or no weld), loading methods (monotonic or cyclic loading), and head shape (small or large circular head and square head). Two full-scale beam-column joint tests were then performed to compare the structural behavior of exterior beam-column joints constructed using two different reinforcement details: i.e. $90^{\circ}$ standard hooks and headed bars. Both joints were designed following the recommendations of ACI-ASCE Committee 352 for Type 2 performance: i.e. the connection is required to dissipate energy through reversals of deformation into inelastic range. The pullout test results revealed that welded head to the stem did not necessarily result in increased pullout strength when compared to non-welded head. Relatively large circular head resulted in higher peak load than smaller circular and square head. Both beam-column joints with conventional $90^{\circ}$ hooks and headed bars behaved similarly in terms of crack development, hysteresis curves, and peak strengths. The joint using the headed bars showed better overall structural performance in terms of ductility, deformation capacity, and energy dissipation. These experimental results demonstrate that the headed bars using relatively small head can be properly designed far use in external beam-column joint.

• Journal of the Korea Concrete Institute
• /
• v.20 no.3
• /
• pp.271-282
• /
• 2008

Specific joint devices composed of end-plates and through bolts are under development to assemble steel beams to PC columns efficiently by dry construction method for the PCS structural system, of which major structural components are precast concrete columns and steel beams. Seismic performance of the joint devices had been evaluated by experimental tests in the previous studies and it was showed that all the performance requirements regarding to strength deterioration, stiffness degradation and energy dissipation capacity were satisfied to the criteria of ACI requirements, but the initial stiffness was not. In order to find out possible causes of the insufficient rigidity of the joint devices and provide the proper measures to improve the performance of the joint accordingly, numerical analyses were carried out by using ABAQUS. Parameters, such as thickness of neoprene pad, conditions of surface between PC column and end-plate, magnitude of pretension forces of through bolts, stiffness of end-plate were taken into consideration. As the result, it was found that the rigidity of the PCS system was negatively affected by the magnitude of initial gaps between PC columns and end-plates, and insufficient stiffness of neoprene fillers and end plates. In order to improve the initial stiffness performance of the joints, measures such as increase of the magnitude of pretension forces on through bolts and increase of the stiffness of end-plate by reducing the bolt pitch and providing adequate stiffeners are recommended.

• Journal of the Korea Convergence Society
• /
• v.11 no.7
• /
• pp.289-295
• /
• 2020

As the importance of the beauty to pursue beauty comes to the fore, the market size of hairdressing industry including hair dyeing is getting bigger. In case of continuously applying an oxidative dyeing agent commonly used in hair salons, as hair damage is inevitable, we investigated morphological changes of hair treated with a neutral oxidative dyeing agent. In the experiment results, Between the control and the 6N-7N experimental groups, there was a significant difference in Max. modulus and Tangential modulus according to Max. load, Max. stress, Max. elongation, Break load, Break stress, Break elongation, and strain section. There were the highest values in Max. load, Max. stress, Max. elongation, Break load, Break stress and Break elongation in the control group, and there was no tendency to decrease significantly according to the treatment of the experimental group. Max. modulus and Tangential modulus according to the strain evaluation section did not show a tendency to increase or decrease constantly, although there was a difference between the control and experimental groups. This study attempts to provide basic data for the development of oxidative dyeing agent that minimizes hair damage and to establish the foundation for understanding the correlation between hair designers' oxidative dyeing agent and hair health.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.10
• /
• pp.96-106
• /
• 2014

Previous academic research on FPGA tools has relied on simple imaginary models for the targeting architecture. As the first step to overcome such restriction, the issues on analytic placement and legalization which are applied to commercial FPGAs have been brought up, and several techniques to remedy them are presented, and evaluated. First of all, the center of gravity of the placed cells may be far displaced from the center of the chip during analytic placement. A function is proposed to be added to the objective function for minimizing this displacement. And then, the density map is expanded into multiple layers to accurately calculate the density distribution for each of the cell types. Early fixation is also proposed for the memory blocks which can be placed at limited sites in small numbers. Since two flip-flops share control pins in a slice, a compatibility constraint is introduced during legalization. Pre-packing compatible flip-flops is proposed as a proactive step. The proposed techniques are implemented on the K-FPGA fabric evaluation framework in which commercial architectures can be precisely modeled, and modified for enhancement, and validated on twelve industrial strength examples. The placement results show that the proposed techniques have reduced the wire length by 22%, and the slice usage by 5% on average. This research is expected to be a development basis of the optimization CAD tools for new as well as the state-of-the-art FPGA architectures.