• Journal of Korean Society of Steel Construction
• /
• v.15 no.1
• /
• pp.1-8
• /
• 2003

In locations where the cost of concrete is relatively high or in situations where the weight of concrete members has to be kept to a minimum, it may be more economical to use hollow reinforced concrete vertic al members. Hollow reinforced concrete colun-ms with a low axial load, a moderate longitudinal steel percentage and a reasonably thick wall were found to perform in a ductile manner at the flexural strength, similar to solid columns. Hollow reinforced concrete columns with a high axial load, a high longitudinal steel percentage, and a thin wall were found, however, to behave in a brittle manner at the flexural strength, since the neutral axis is forced to occur away from the inside face of the tube towards the section centroid and, as a result, crushing of concrete occurs near the unconfined inside face of the section. If, however, a steel tube is placed near the inside face of a circular hollow column, the column can be expected not to fail in a brittle manner through the disintegration of the concrete in the compression zone. A design recommendation and example through the moment-curvature analysis program for curvature ductility are herein presented. A theoretical moment-curvature analysis for reinforced concrete columns, indicating the available flexural strength and ductility, can be conducted, providing that the stress-strain relation for the concrete and steel are known. In this paper, a unified stress-stain model for confined concrete by Mander is developed foi members with circular sections.

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.4
• /
• pp.293-301
• /
• 2013

This study discusses the feasibility of coffee bean residue as a raw material of medium-density fiberboard (MDF). In this relation, the effect of coffee bean residue known as an absorbent material on the physical and mechanical properties of MDF manufactured at its different addition level. Coffee bean residue which is a by-product of coffee mill and large amount of waste left over after processing for instant coffee was added at the level of 3, 6, and 9% on dry basis and urea formaldehyde resin was used as the adhesive. The MDF made with mixture of wood fiber and coffee bean residue was tested for physical and mechanical properties as well as formaldehyde emission. The bending strength and internal bonding strength of the MDF made with mixture of wood fiber-coffee bean residue were higher than that of the KS standard in randomized mat structure type, but not in layered mat structure type. Also, the physical properties of MDF made with mixture of wood fiber-coffee bean residue showed a considerable improvement in thickness swelling over the commercial MDF. More importantly, the formaldehyde emission rate of MDF made with mixture of wood fiber-coffee bean residue met the KS standard and was close to that of commercial MDF. These results showed the feasibility of coffee bean residue as a raw material for the production of environmentally-friendly MDF. Additional works on adhesive-coffee bean compatibility, improvement of moisture absorption effect and reduction the formaldehyde emission rate by carbonization of coffee bean residue may be required.

• Economic and Environmental Geology
• /
• v.50 no.2
• /
• pp.145-157
• /
• 2017

Because of Recent intensive rainfall, nationally landslides and slope failure phenomenon has been frequently occur. Providing proposed-measures to the natural disasters that occur in these localities and the slope, must be derived ground of strength parameters(shear strength) as a design input data. However, it is such as extra deforestation and a lot of economic costs in order to make the access to the current area and the slopes ground survey is required. Thus, by small dynamic cone penetration test machine using the human to carry in the field, it is possible to easily measure the characteristics and strength constant of the ground of more than one region. In this study through researching analysis of the domestic and foreign small dynamic cone penetration test method, it has proposed a cone material and test methods suitable for the country. Cone penetration test Nc in the field has comparated with analysis of the value and the standard penetration test N value. And, in addition to this, direct shear test and borehole shear test were performed by depth, bedrock, and soil type and passing #200 and the correlation of the Nc value. In particular, in the present study, for the sandy soil that has distict distribute in mountain, it is proposed relation of shear strength corresponding to the Nc value (cohesion and internal friction angle) in order to calculate such effective ground shear strength.

• Korean Journal of Psychosomatic Medicine
• /
• v.17 no.2
• /
• pp.82-89
• /
• 2009

Objectives : Anxiety is a common co-morbid symptom in patients with epilepsy, which can affect the treatment and prognosis of epilepsy patients. This study is designed to compare the characteristics of anxiety between epilepsy patients and normal controls and also analyze them in epilepsy patients by examining both seizure-related and socio-demographic variables. Methods : As cross-sectional study, 80 epilepsy patients were enrolled from January to July 2008. The State-Trait Anxiety Inventory-(STAI) was used to assess the characteristics of anxiety. STAI is composed of transitory episodes of anxiety-(state subscale of STAI ; STAI-S) and stable personality features presenting chronic levels of anxiety-(trait subscale of STAI ; STAI-T). As controls, 113 healthy age-and sex-matched people were included. Results : The mean score of STAI-S and STAI-T were not different in both groups(STAI-S ; p=0.998, STAIT ; p=0.343). Within patients, patients without occupational engagement showed higher STAI-S(p<0.001) and tendency to higher STAI-T(p=0.052). Patients with depression showed higher score in both modalities(STAIS and STAI-T ; p<0.001). Patients with aura showed higher STAI-T(p=0.031). Conclusions : STAI-S and STAI-T was not significantly different between patients and controls. Of 3 factors related to anxiety, higher STAI-T in patients with aura is likely to represent misunderstanding internal and external changes as an aura and worrying about impending seizure. Occupational engagement and depression had relation to both STAI-S and STAI-T and more concern is needed to evaluate the risk of anxiety and manage it appropriately.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.39 no.4
• /
• pp.106-113
• /
• 1997

Dynamic loading of structures often causes excursions of stresses well into the inelastic range, and the influence of the geometric changes on the dynamic response is also significant in many cases. Therefore, both material and geometric nonlinearity effects should be considered in case that a dynamic load acts on the structure. A structure in a nuclear power plant is a structure of importance which puts emphasis on safety. A nuclear container is a pressure vessel subject to internal pressure and this structure is constructed by a reinforced concrete or a pre-stressed concrete. In this study, the material nonlinearity effect on the dynamic response is formulated by the elasto-viscoplastic model highly corresponding to the real behavior of the material. Also, the geometrically nonlinear behavior is taken into account using a total Lagrangian coordinate system, and the equilibrium equation of motion is numerically solved by a central difference scheme. The constitutive relation of concrete is modeled according to a Drucker-Prager yield criterion in compression. The reinforcing bars are modeled by a smeared layer at the location of reinforcements, and the steel layer model under Von Mises yield criteria is adopted to represent an elastic-plastic behavior. To investigate the dynamic response of a nuclear reinforced concrete containment structure, the steel-ratios of 0, 3, 5 and 10 percent, are considered. The results obtained from the analysis of an example were summarized as follows 1. As the steel-ratio increases, the amplitude and the period of the vertical displacements in apex of dome decreased. The Dynamic Magnification Factor(DMF) was some larger than that of the structure without steel. However, the regular trend was not found in the values of DMF. 2. The dynamic response of the vertical displacement and the radial displacement in the dome-wall junction were shown that the period of displacement in initial step decreased with the steel-ratio increases. Especially, the effect of the steel on the dynamic response of radial displacement disapeared almost. The values of DMF were 1.94, 2.5, 2.62 and 2.66, and the values increased with the steel-ratio. 3. The characteristics of the dynamic response of radial displacement in the mid-wall were similar to that of dome-wall junction. The values of DMF were 1.91, 2.11, 2.13 and 2.18, and the values increased with the steel-ratio. 4. The amplitude and the period of the hoop-stresses in the dome, the dome-wall junction, and the mid-wall were shown the decreased trend with the steel-ratio. The values of DMF were some larger than those of the structure without steel. However, the regular trend was not found in the values of DMF.

• Journal of Distribution Science
• /
• v.10 no.3
• /
• pp.31-42
• /
• 2012

After the rapidly changing business management environment and financial crisis, high prices and domestic recession in Korea posed threats to the business survival of small and medium enterprises (SMEs). This paper looks at the potential of micro business owners for sustainable development: those who have a spirit of entrepreneurship and the potential to be a hidden champion. Our study of micro business values uses structure equation modeling by LISREL. We have done so in order to understand the foundation of management innovation and success model of micro enterprise by increasing the entrepreneurship and management performance relationship analysis. A micro-enterprise is a type of small business, found only in Korea, often registered as having ten or fewer employees. We examine the successful type of hidden champions and the influence of entrepreneurship on start-ups in business. As compared to past research on the SME entrepreneurship, this study segments small businesses even further. Small business entrepreneurship was classified into three forms that are most appropriate for the Korean situation today: innovation, risk-taking, and pro-activeness. This research is meaningful as it is Korea's first empirical analysis on four business types: wholesale and retail sales, food and lodging business, service business, and manufacturing business. Thus far, research on small business entrepreneurship was carried out using small-scale investigative analysis. However, this research attempted to develop a model that can explain a cause-effect relation of the motivational level when it comes to the difference of entrepreneurship by each business type and small business start-up success factors. Various conceptual and operational definitions could be developed in a diverse and precise manner. Independent variables that are related to the success of small businesses can be developed additionally to examine the success factors related to the systematization in detailed manner. The research showed that the innovation, risk-taking and pro-activeness of the manifested difference in the degree of perception depending on the type of small businesses. Among the four business types, the ones that manifested the highest successful start-up rates were food, service, wholesale and retail sales and manufacturing. Results after conducting the regression analysis are shown on, which proves that the small business entrepreneurship exerts direct effect on the financial management performance of small businesses. In other words, small business entrepreneurship exerts a positive effect on the small business financial success and management performance. The R² value is 0.61. It is possible to know that the perception of systematization and variables on attitude explains the 61% of the success for small self-employed businesses management performance. We define start-up key factors that are helpful to achieve internal growth of firms by finding business survival strategies. The results also focus on Korean government policy for micro enterprise and small business support.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.2
• /
• pp.807-813
• /
• 2016

Triple-negative breast cancers constitute about 15% of all cases, but despite their higher response to neoadjuvant chemotherapy, the tumors are very aggressive and associated with a poor prognosis as well as a higher risk of early recurrence. This study was retrospectively performed on 101 patients with stage II and III invasive breast cancer who received 6-8 cycles of neo-adjuvant chemotherapy. Out of the total, 23 were in the triple negative breast cancer subgroup. Nuclear Ki-67 expression in both the large cohort group (n=101) and triple negative breast cancer subgroup (n=23) and its relation to the pathological response were evaluated. The purpose of the study was to identify the predictive value of nuclear protein Ki-67 expression among patients with invasive breast cancers, involving the triple negative breast cancer subgroup, treated with neoadjuvant chemotherapy in correlation to the rate of pathological complete response. The proliferation marker Ki-67 expression was highest in the triple negative breast cancer subgroup. No appreciable difference in the rate of Ki-67 expression in triple negative breast cancer subgroup using either a cutoff of 14% or 35%. Triple negative breast cancer subgroup showed lower rates of pathological complete response. Achievement of pathological complete response was significantly correlated with smaller tumor size and higher Ki-67 expression. The majority of triple negative breast cancer cases achieved pathological partial response. The study concluded that Ki-67 is a useful tool to predict chemosensitivity in the setting of neoadjuvant chemotherapy for invasive breast cancer but not for the triple negative breast cancer subgroup.

• The Journal of Korean Society for Radiation Therapy
• /
• v.18 no.2
• /
• pp.67-73
• /
• 2006

Purpose: The number of patients receiving radiotherapy has increased every year and will keep increasing in the future. Therefore, the technique of radiotherapy is developing from day to day, as a result of it, the quantities of image and data used for radiotherapy are also considerably increasing. Therefore, there have been many difficulties in storing, keeping and managing them. Then, we developed and applied this system for improving complicated work process as well as solving these problems with the collaboration Medical Information Team. Materials and Methods: We exported its image at R & V (Record and Verify: Varis vision, Varian, USA) system and planning system after giving some code to be able to access from management system(RO) for department of radiation oncology to PACS. And, we programmed their information by using necessary information among many information included in DICOM head. Results: All images and data generated by our working environment (Simulation CT, L-gram image and internal body structure, DRR, does distribution )were realized at PACS and it became to be possible for clear image to be printed from any computer in department of radiation oncology. Conclusion: It was inevitable to use film during radiotherapy for patients in the past, however, due to the development of this system, film-less system became to be possible. Therefore, the darkroom space and its management cost in relation to the development process disappeared and it became to be unnecessary for spending tangible and intangible financial expense including human resources, time needed for finding film storing space and film and purchasing separate storing equipment for storing images. Finally, we think this system would be very helpful to handle ail complicated processes for radiotherapy and increasing efficiency of overall working conditions.

• Journal of Korea Technology Innovation Society
• /
• v.18 no.1
• /
• pp.28-48
• /
• 2015

This study is public R & D institutions report to verify what the impact factors on the course of progress of industrialization based on technology companies who previously received prior to the developed technology, what policies and plans for the next requirements based on this by offering the implications for business rate was to contribute to the improvement of the public research institution technology transfer. In this study, the influence factors on technology commercialization derived through the analysis of existing and previous studies, the characteristics of the previously received corporate environmental characteristics and previous technologies through a survey of the company received a technology transfer from public research institutions commercialization decisions and contributions, including sales and commercialization of the results were analyzed by logistic regression analysis demonstrated how to have relevance. Analysis, and linkage with high production company has an existing case of IT technology transfer, commercialization of higher technical success rate was higher compatibility. On the other hand, were observed and expected success rate were higher when a rather commercialized technologies independently be earlier than if participating in joint research in the development of the technology, unlike previously, completeness of the prior art did not significantly affect. This study has the following policy implications. Public research institutions have developed technologies are commercialized to figure out what the requirements of the technical aspects of consumer technologies in order to create economic wealth. And for technology commercialization for enough technical competencies to absorb the technology, and that the technology and considering the link between business and technology commercialization success to be applied. This study has some limitations. First, the sample size was not sufficient. In relation to the presence and participation of corporate success and commercialization of the R & D process, with many previous studies are needed more in-depth analysis by leading research in the sense that different results are obtained. Also did not reflect the will or the corporate culture, management and organizational skills and belongs to the external environment and internal corporate enterprises industry characteristics affecting the success of corporate management of the business. And lacked sufficient consideration of the various technical characteristics present in the form of joint research and industry. Finally, there is a limit of generalizations about other industries.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.3
• /
• pp.551-561
• /
• 2017

This study attempts to determine the strategy to improve the quality of staff supervision by exploring the experiences of the staff supervision in community welfare centers. For this purpose, multiple case study was performed by conducting in-depth interviews with 10 supervisors for the analysis data and analyzing the resulting themes. The key subjects from their experience were 'Supervisors recognize and prepare the supervision as Challenge and Aspiration', 'Supervision leaves only chaos and frustration', and 'Inspiration from the supervisor and infinite effort result in fruit'. Based on these results, this study suggests the following practical suggestions for the educational, administrative and supportive functions of Supervision. First, educational functions should be proposed as an extension of supervisor's education opportunities and manuals related to educational growth of supervision. Second, the administrative function should be changed to evaluate social welfare institution's evaluation framework so as to evaluate the supervision internal regulation and supervision according to it and various supervision models should be developed. Third, supportive supervision function that can be encouraged for supervisees should be enhanced. This study was meaningful because it presents specific suggestions for supervisors and supervisee's relation and situation in the community welfare center through the qualitative research method.