• Nuclear Engineering and Technology
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• v.47 no.6
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• pp.756-765
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• 2015

Background: Fibers have been used in cement mixture to improve its toughness, ductility, and tensile strength, and to enhance the cracking and deformation characteristics of concrete structural members. The addition of fibers into conventional reinforced concrete can enhance the structural and functional performances of safety-related concrete structures in nuclear power plants. Methods: The effects of steel and polyamide fibers on the shear resisting capacity of a prestressed concrete containment vessel (PCCV) were investigated in this study. For a comparative evaluation between the shear performances of structural walls constructed with conventional concrete, steel fiber reinforced concrete, and polyamide fiber reinforced concrete, cyclic tests for wall specimens were conducted and hysteretic models were derived. Results: The shear resisting capacity of a PCCV constructed with fiber reinforced concrete can be improved considerably. When steel fiber reinforced concrete contains hooked steel fibers in a volume fraction of 1.0%, the maximum lateral displacement of a PCCV can be improved by > 50%, in comparison with that of a conventional PCCV. When polyamide fiber reinforced concrete contains polyamide fibers in a volume fraction of 1.5%, the maximum lateral displacement of a PCCV can be enhanced by ~40%. In particular, the energy dissipation capacity in a fiber reinforced PCCV can be enhanced by > 200%. Conclusion: The addition of fibers into conventional concrete increases the ductility and energy dissipation of wall structures significantly. Fibers can be effectively used to improve the structural performance of a PCCV subjected to strong ground motions. Steel fibers are more effective in enhancing the shear performance of a PCCV than polyamide fibers.

• Journal of Korea Society of Industrial Information Systems
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• v.12 no.3
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• pp.47-59
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• 2007

IPv4 NAT, which often used in households or under SOHO environments, is one of the factors that delays IPv6 propagation. As IPv4 NAT does not operate properly under the transition mechanism like ISATAP or 6to4 that acts as IPv6-in-IPv4 tunneling type, Microsoft proposed Teredo in order to resolve this issue. However, tunneling transition mechanism like Teredo has a security problem. That is, being tunneled packets have dual IP headers; general firewall systems apply the filtering rules only to the outer header but not inner header when these packets pass the firewall. Furthermore, attacks using unregistered server and relay can take place in Teredo. To resolve these problems, we propose a new packet filtering mechanism exclusively for Teredo. The proposed packet filtering mechanism was designed and implemented by using Linux Netfilter and ip6tables. Through functional and experimental performance tests, this packet filtering system was found operating properly and solving the Teredo packet filtering problems without serious performance degradation.

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.519-529
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• 2015

The purpose of this study is to examine the determinant factors of maintaining employment in young adults with intellectual disabilities who took part in a vocational training program and was employed. The determinant factors were from four areas, such as physical competence, job-related task performance, emotional behaviors, and functional adaptive behaviors. 64 young adults with intellectual disabilities participated in this study. The participants' capacities were examined during the program, and then their job retention was examined through a follow-up survey six month after the end of the program. Tests contained hand dexterity, grasp strength, finger strength, visual-perception, Survey of Functional Adaptive Behaviors, and Observational-Emotional Inventory-Revised. After data collection, the data were analyzed by binary logistic regression. The results indicated that dexterity in both hands (OR= 1.123) in physical competence, anxiety (OR= .733) and socialization (OR= .429) in emotional behaviors, and academic skills (OR= 1.077) and vocational skills (OR= 1.542) in functional adaptive behaviors were significant determinant factors. These significant factors which affected job attention were consistent with the results from previous studies, and should be considered when designing and constructing an effective career and vocational education program for young adults with intellectual disabilities.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.261-266
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• 2015

As performance of electronic personal dosimeter (EPD) used for auxiliary personal dosimeter in nuclear power plants (NPPs) has been being continuously improved, we investigated application cases in Korea and other countries and also tested it in NPPs to assess the performance of EPD for external radiation dosimetry. Result of performance tests done in domestic NPPs was similar to those obtained by IAEA in cooperation with EURADOS (IAEA-TECDOC-1564). In addition, EPD/TLD dose ratio has shown similar tendency of EPD/Film-badge dose ratio from the research by the Japan Atomic Power Company (JAPC) and EPD provided more conservative value than TLD or Film-badge. Although some EPD's failures have been discussed, EPD has shown continuous improvement according to the report of Institute of Nuclear Power Operation (INPO) and data from domestic NPPs. In conclusion, It is considered that the general performance of EPD is adequate for external radiation dosimetry compared with that of TLD, providing appropriate performance checking procedure and alternative measures for functional failure.

• Journal of Hospice and Palliative Care
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• v.8 no.2
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• pp.183-189
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• 2005

Purpose: Despite the advance of medical science, the number of cancer patient have increased and the mortality rate is also on the rise. Therefore, a perfect cure for cancer is crucial, but the value and meaning of the remaining life for the patient are also becoming more and more important. The principal aim of this study is to examine the differences in the quality of life, physical and psychosocial symptoms according to the performance status of terminal cancer patients. Methods: We evaluated the performance status, demographical data, blood analysis and quality of life of cancer patients who visited the Department of family Medicine at Myoung-ji Hospital in Korea between September 1, 2003 and August 31, 2005. Their performance status (ECOG) was divided into two groups ($ECOG\;0{\sim}1/ECOG\;2{\sim}4$) and analyzed by ANOVA to see if there was a difference in their blood analysis and quality of life. A P value of less than 0.05 was considered to be significant. Results: A total of 104 patients were evaluated, among which 71 patients (23 male and 48 female) scored $0{\sim}1$, and 33 patients (8 males and 25 females) scored $2{\sim}4$ in the ECOG. The blood analysis showed that patients whose performance status was $2{\sim}4$ had lower levels of lymphocytes, hemoglobin, protein, albumin and sodium. The evaluation on their quality of life showed that the overall health status of patients with $2{\sim}3$ functional ability were poor (P=0.02). Also, from a functional perspective, these patients had poor physical (P=0.05) and role (P=0.01) scores, and in terms of symptoms, they showed a significant loss of appetite. Conclusion: If a patient's performance status was poor, levels related to certain nutritions were also found to fall in blood tests, thereby leading to an overall weakened state of health. However, there was no difference in symptoms except for a loss of appetite. In conclusion, it is most important to increase the appetite in patients with poor performance status.

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.535-541
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• 2020

A conventional elastic material replacement and performance evaluation are very complicated and time-consuming, and it is difficult to know when to replace the elastic material in advance. By comparing with the product limit and the functional limit, the necessity of elastic material replacement and the improvement of track support stiffness according to replacement can be immediately demonstrated based on experimental data. Using an evaluation system of track support stiffness, the performance evaluation data for elastic materials obtained through field tests using software for track support stiffness is integrated and managed on the administrator's computer. Therefore, the replacement plan is established and maintenance history is managed by identifying the replacement time and location of elastic materials. It is possible to evaluate the performance and condition of the elastic material at the various points during the working time of the track inspection and the track performance (track support stiffness) and durability of the elastic material (aging level, spring stiffness variation rate, etc.) at the operation condition. The elastic material could be replaced timely, and the deterioration of the elastic material can be continuously monitored.

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.215-224
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• 2019

According to the recent civil engineering construction work site which is a complex process, development of multi-functional geotextiles is required. In this study, the characteristics of five different modified cross-section fiber yarns for the selection of wicking yarns were analyzed and yarns that can achieve target properties were selected. Experimental prototype geotextiles suitable for horizontal wicking drain property and reinforcement was developed and its tensile strength, 2% secant modulus, vertical water permeability, AOS, friction characteristics by the direct shear method, and vertical/horizontal wicking test were analyzed. These tests are conducted to verify the performance of the geotextiles with horizontal wick drain property, separation and reinforcement developed in this study. As a results of the indoor soil box test, it was confirmed that the geotextiles using the wicking yarn sufficiently exhibited the function of discharging excess pore water in the horizontal direction.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.2
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• pp.179-184
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• 2009

The Fuel Test Loop(FTL) which is capable of an irradiation testing under a similar operating condition to those of PWR(Pressurized Water Reactor) and CANDU(CANadian Deuterium Uranium reactor) nuclear power plants has been developed and installed in HANARO, KAERI(Korea Atomic Energy Research Institute). It consists of In-Pile Section(IPS) and Out-of Pile System(OPS). The IPS, which is located inside the pool is divided into 3-parts; the in-pool pipes, the IVA(IPS Vessel Assembly) and the support structures. The test fuel is loaded inside a double wall, inner pressure vessel and outer pressure vessel, to keep the functionality of the reactor coolant pressure boundary. The IVA is manufactured by local company and the functional test and verification were done through pressure drop, vibration, hydraulic and leakage tests. The brazing technique for the instrument lines has been checked for its functionality and performance. An IVA has been manufactured by local technique and have finally tested under high temperature and high pressure. The IVA and piping did not experience leakage, as we have checked the piping, flanges, assembly parts. We have obtained good data during the three cycle test which includes a pressure test, pressure and temperature cycling, and constant temperature.

• Tunnel and Underground Space
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• v.21 no.4
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• pp.264-273
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• 2011

Bentonite buffer is one of the major components of an engineered barrier for an HLW (High-Level Waste) repository. The bentonite buffer is significantly exposed to the decay heat from radioactive wastes, the inflow of groundwater from the surrounding rock of the repository, and the high swelling pressure of densely-compacted bentonite that comes in contact with the groundwater. Therefore, it is essential to understand the THM (Thermal-Hydro-Mechanical) behavior of the bentonite buffer and to acquire the input data of its related constitutive models for the performance and safety assessment of an HLW repository. This paper analyzed the THM properties which have been obtained by conducting laboratory tests with a candidate buffer material for a Korean HLW repository. Moreover the formulation recipe of the reference bentonite buffer was defined on the basis of functional criteria, thus suggesting the THM properties which correspond to the formulation recipe of the reference bentonite buffer.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.9-18
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• 2014

PURPOSES : The objective of this study is to evaluate the applicability of the pitch, which is produced during SDA petroleum upgrading process, as a pavement paving material. In order for the purpose, the physical and chemical properties of the pitch are analyzed, and then the various plasticizers are applied in the pitch. METHODS : Two types of pitch are selected from oil refinery companies, which are owned the SDA petroleum upgrading process. Also, two types of asphalt binders, PG 64-22 and PG 58-22, are employed to compare with the pitch because these two types of asphalt binders are currently used as paving materials. For the chemical property of the pitch, the composition of SARA (Saturate, Aromatic, Resin, Asphaltene), the elementary composition, and the functional group are analyzed. For the physical property of the pitch, the basic material property tests, such as penetration test, softening point test, flash point test, ductility test, and rotational viscometer test, are performed. Also, the DSR (Dynamic Shear Rheometer) test and the BBR (Bending Beam Rheometer) test are conducted using asphalt binder specimens obtained by both short term aging (Rolling Thin Film Oven, RTFO) and long term aging (Pressure Aging Vessel, PAV) processes. The rheological property of each pitch type is evaluated as a function of temperatures and loading cycles. PG 64-22 asphalt binder is used as a control material. RESULTS AND CONCLUSIONS : The Pitch may not be suitable for the pavement paving material without modifications, but the pitch can be used as alternatives of modified addictive or asphalt. If low molecular component, such as saturate and aromatic components, are added in the pitch based on the development of various plasticizers, it has a strong possibility for the pitch to be used as a alternative. However, in order to verify the performance property of the pitch, further research is needed.