• Journal of the Korean Geotechnical Society
• /
• v.19 no.3
• /
• pp.5-13
• /
• 2003

The soil nailing is one of the useful support-system in urban excavation because of the presence of other structures in the vicinity Since the soil nailing system was introduced, model experiments and theoretical studies have been performed to investigate behavior of soil nailed wall. However, there are few data in the case of multi-layered soil strata just like Seoul Metropolitan area in Korea. The feed back analyses are carried out using the measured wall displacement data for soil nailing construction sites with multi-layered strata in order to analyze the distance and the coefficients of extension zone of ground behind soil nailed wall. As a result, the distance of extension zone increased with increasing of the final excavation depth and the ratio of the distance to the final excavation depth was shown to be about 94% of the final excavation depth. Also, the coefficients of extension zone increased with enlargement of soil layer thickness and converged into constant value of 1.05. On the other hand, the maximum vertical displacements by the feed back analysis and Caspe's method were shown to be approximately 80%, 150~280% of the maximum horizontal displacement respectively.

• Safety and Health at Work
• /
• v.12 no.4
• /
• pp.432-438
• /
• 2021

Background: We aimed to investigate the prevalence of low back pain (LBP) and its associated agricultural work-related, biomechanical factors among this population. Methods: We analyzed initial survey data from the Safety for Agricultural Injury of Farmers cohort study involving adult farmers in Jeju Island. The prevalence of LBP was calculated with associated factors. Results: In total, 1,209 participants were included in the analysis. The overall prevalence of LBP was 23.7%. Significant associations for LBP were the type of farming activity, length of farming career, prior agricultural injury within 1 year, and stress levels. Multivariate logistic regression analysis revealed three biomechanical factors significantly related to LBP: repetitive use of particular body parts; the inappropriate posture of the lower back and neck. Conclusions: Some occupational, and biomechanical risk factors contribute to LBP. Therefore, postural education, injury prevention education, and psychological support will be needed to prevent LBP.

• Korean journal of communication and information
• /
• v.36
• /
• pp.287-323
• /
• 2006

This study attempted to find out that organizational culture and organizational support are the main factors of an effect on team, a kind of making unit of broadcasting programming, commitment. And especially this research tried out that each organizational culture type had an effect differently on team commitment using of Linear Structural Equation Modeling(LISREL). In order to empirically test to the research model, data were collected by 280 terrestrial Broadcasting PD in Seoul. Result showed that each organizational culture has a differential influence on the path and effect of organizational support and team commitment. The educational system and production back up of the Organizational support system have not enough to support and promote the team commitment except reward system. As a consequence, Broadcasting organization make a strategy considering of dominant organizational culture type.

• Journal of The Korean Society of Integrative Medicine
• /
• v.2 no.1
• /
• pp.109-116
• /
• 2014

Purpose : The purpose of this study was to perform the calf-raise exercise on the stable support surface and unstable support surface for comparing deference of the gastrocnemius thickness changes that measured by ultrasonography. Method : Subjects stand on unstable support surface and a stable support surface with both feet. Keeping calf-raise position in the 3 seconds, and then had to return back to the starting position. Total of 3 sets of 15 repetitions performed and give a 30-second rest between each set. In this way, exercise performed 3 times a week, performed a total of 6 weeks. Result : 1. gastrocnemius muscle thickness before and after exercise in experimental group A was significantly different(p<.05). 2. gastrocnemius muscle thickness before and after exercise in experimental group B was significantly different(p<.05). 3. gastrocnemius muscle thickness in experimental group A and experimental group B was significantly difference(p<.05). Conclusion : In conclusion, calf-raise exercise on unstable support surface was more efficient than stable support surface for increasing thickness of gastrocnemius.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.5 no.2
• /
• pp.73-84
• /
• 2007

This study aims to examine changes from differences in the lumbar scoliosis angle and iliac crest height due to abnormal and habitual posture shown in unilateral weight load at standing posture and suggest data for preventing and treating lumbago. The subjects of this study are 16 lumbago patients between twenties and forties with chronic lumbago over six months, but without neurological symptoms. As a result of photographing front and back with three conditions such as weight load on both sides and left or right unilateral weight load posture in order to examine changes of lumbar scoliosis and iliac crest according to changes of posture at unilateral weight load, while scoliosis angle and iliac crest height by habitual unilateral support were increased, those by opposite support were decreased. In conclusion, it was found that habitual unilateral weight load may cause continuous distortion of spinal angle and change of iliac crest height and these may be a factor of lumbago. Therefore, if habitual unilateral weight load state is kept continuously, distortion of lumbar angle and iliac crest height may be greater and common efforts to change habitual unilateral weight load are needed.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.17 no.3
• /
• pp.134-140
• /
• 2018

This paper describes the design and fabrication of an automatic alignment and loading system for workpieces. To move a workpiece to a chucking position of a machine tool using a gantry robot, an automatic aligning device is required to load the workpiece before machining and automatically align them. The automatic alignment system was conceptually designed, and the structural analysis was performed for the main parts such as the top plate, center support, front and back support, and support shaft. Based on the structural analysis results, the size of these structures was determined. The automatic alignment system was manufactured, and the vertical movement characteristics of the workpiece up-and-down movement device and the rotation characteristics of the workpiece rotation device were experimentally examined. The result has confirmed that they operate normally.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1141-1145
• /
• 2005

This paper proposes a robust tension control algorithm for the let-off and take-up system driven by servo motor which is robust to disturbance and tension variation by using SVR(Support Vector Regression). Quality of textile goods in fiber manufacturing process highly depends on control of let-off, take-up and tension which are essential for constant tension control of yarn and textile fabrics and correct length of them. The physical properties of textile fabrics are very sensitive to several factors(temperature, humidity, radius change of warp beam etc.) which result in tension change. Rapid development of fiber manufacture machine for higher productivity requires control system for let-off, take-up and tension for robustness to sharp tension-variation and quick response. The validity and the usefulness of the proposed algorithm are thoroughly verified through numerical simulation.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.15 no.1
• /
• pp.16-27
• /
• 2012

In multi-interface multi-channel(MIMC) based tactical ad hoc networks, QoS support for required operational capacity is one of the main challenging issues for multi-hop transmissions. To support QoS in such a harsh environment, we propose a novel MAC scheme to minimize multi-hop as well as per-hop delay. The current IEEE 802.11 MAC protocols should contend to reserve the channel resource at every hop by each sender. The every-hop channel contention results in a degradation of end-to-end delay for multi-hop transmissions. The basic idea of our scheme is to make a "multi-hop reservation" at the MAC layer by using the modified RTS frame. It contains additional information such as destination information, packet priority, and hop count, etc. In addition, we differentiate the contention window area according to the packet priority and the number of hops to deliver packets in the predefined allowed latency. Our scheme can minimize the multi-hop delay and support the QoS of the critical data in real time(i.e., VoIP, sensing video data, Video conference between commanders). Our simulation study and numerical analysis show that the proposed scheme outperforms the IEEE 802.11 MAC.

• Geomechanics and Engineering
• /
• v.12 no.3
• /
• pp.483-503
• /
• 2017

Uncertainty is a fact belonging to engineering practice. An important uncertainty that sets geotechnical engineering is the variability associated with the properties of soils or, more precisely, the characterization of soil profiles. The reason is due largely to the complex and varied natural processes associated with the formation of soil. Spatial variability analysis for the study of the stability of natural slopes, complementing conventional analyses, is able to incorporate these uncertainties. In this paper the characterization is performed in back-analysis for a case of landslide occurred to verify afterwards the presence of the conditions of shear strength at failure. This approach may support designers to make more accurate estimates regarding slope failure responding, more consciously, to the legislation dispositions about slope stability evaluation and future design. By applying different kriging techniques used for spatial analysis it has been possible to perform a 3D-slope reconstruction. The predictive analysis and the areal mapping of the soil mechanical characteristics would support the definition of priority interventions in the zones characterized by more critical values as well as slope potential instability. This tool of analysis aims to support decision-making by directing project planning through the efficient allocation of available resources.

• Journal of Korean Institute of Industrial Engineers
• /
• v.25 no.4
• /
• pp.459-465
• /
• 1999

A new-concept VDT workstation chair with adjustable keyboard/mouse support was proposed to minimize physical discomfort and the risk of cumulative trauma disorders (CTDs) at work sites in this study. First, a three-dimensional human modeling tool $(SAFEWORK^{(R)})$ was used to design the new chair satisfying the anthropometric specifications of Korean population. Second, based upon the result of 3-D graphical simulation, a mock-up chair was constructed with an adjustable keyboard/mouse support directly attached to the chair body. Third, muscle fatigue and subjective discomfort were measured to evaluate the newly developed chair. An experiment was conducted to compare the new workstation chair to the traditional computer chair without keyboard/mouse support. Six volunteer subjects participated in six one-hour word-processing sessions with two different chairs and three different postures. Statistical results indicate that the new-concept VDT chair generally improved subjective comfort level and reduced fatigue in finger flexor/extensor and low back muscle. In conclusion, this new VDT workstation chair is expected to reduce physical discomfort and prevent occupational CTD problems in the long run. Implications of the new design and suggestions for the further development are also addressed.