• Journal of Preventive Medicine and Public Health
• /
• v.53 no.5
• /
• pp.332-341
• /
• 2020

Objectives: The purpose of this study was to investigate the association between the Basic Old-Age Pension (BOP), which is a non-contributory pension, and depression in BOP beneficiaries in Korea. Methods: We used the second and third waves (2007-2008) of the Korea Welfare Panel Study to identify the effect of the BOP on mental health in the year of its introduction. The Center for Epidemiological Studies-Depression Scale, applied in a Korean context, was used to evaluate mental health. To analyze the effect of the BOP, a difference-in-difference approach was used in analyses of all subjects and subgroups. Results: For this study population of 760 adults, the BOP did not have a statistically significant relationship with depression in its beneficiaries. After controlling for type of household, the BOP was still not associated with lower reporting of depression, either in single-beneficiary or double-beneficiary households, in the year of the benefit. Conclusions: The BOP policy had no significant relationship with the level of depression among recipients. However, this should not be interpreted as implying that income subsidy programs for older adults, such as the BOP, do not affect mental health, considering the importance of economic hardship in this population and the program's socioeconomic effects.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.10a
• /
• pp.373-376
• /
• 2005

In recent years, there has been a growing need fur productivity improvement of ACS wire (Aluminum clad Steel wire) In optical communication market. So, it is necessary to improve the production speed and following quality of ACS wire to reduce the unit cost of the products. In this study, the pre-heating temperature and cladding speed is chosen as the factors can influence the mechanical and metallurgical properties during cladding, and the changing behavior of mechanical property and microstructure by controlling above two factors are investigated. And the bearing length and approach angle in cladding die are selected as the important elements for designing optimum die enabling high speed cladding. So we carried out FE(Finite Element) analysis using the above two elements as variables. This paper aims to understand the change of mechanical properties and microstructure according to the change of each factor during cladding and suggest the optimized cladding condition to get the best quality of OPGW. And also we would like to introduce the optimum die structure that enables high-speed cladding.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.26-26
• /
• 2011

Self-assembled monolayers (SAMs) prepared by sulfur-containing organic molecules on metal surfaces have drawn much attention for more than two decades because of their technological applications in wetting, chemical and biosensors, molecular recognition, nanolithography, and molecular electronics. In this talk, we will present self-assembly mechanism and two-dimensional (2D) structures of various organic thiol SAMs on Au(111), which are mainly demonstrated by molecular-scale scanning tunneling microscopy (STM) observation. In addition, we will provide some idea how to control 2D molecular arrangements of organic SAMs. For instance, the formation and surface structure of pentafluorobenzenethiols (PFBT) self-assembled monolayers (SAMs) on Au(111) formed from various experimental conditions were examined by means of STM. Although it is well known that PFBT molecules on metal surfaces do not form ordered SAMs, we clearly revealed for the first time that adsorption of PFBT on Au(111) at $75^{\circ}C$ for 2 h yields long-range, well-ordered self-assembled monolayers having a $(2{\times}5\sqrt{13})R30^{\circ}$ superlattice. Benzenethiols (BT) SAMs on gold usually have disordered phases, however, we have clearly demonstrated that the displacement of preadsorbed cyclohexanethiol self-assembled monolayers (SAMs) on Au(111) by BT molecules can be a successful approach to obtain BT SAMs with long-range ordered domains. Our results will provide new insight into controlling the structural order of BT or PFBT SAMs, which will be very useful in precisely tailoring the interface properties of metal surfaces in electronic devices.

• Journal of Marine Bioscience and Biotechnology
• /
• v.6 no.1
• /
• pp.17-25
• /
• 2014

Periodically, harmful algal blooms (HABs) have occurred, with impacts on various areas including public health, tourism, and aquatic ecosystems, especially aquacultured and caged fisheries. To prevent or manage invasions of HABs into fish farms on an emergency basis, many methods have been proposed. Frequently over the past 30 years in coastal countries, treatments of clay and clay mixed with polyaluminum chloride (PAC) and chitosan have been tested for HAB-removal effectiveness in both the laboratory and the field. In Korea, yellow loess clay (hwangto) has been dispersed using electrolytic clay dispensers, both to decrease the amount of yellow loess clay's usage in containers and enhance HAB-removal efficiency. However, this emergency method has limitations, among which is the requirement for more effective controlling agents for field applications. Thus, in this paper, we review technologies for clay-based red tides prevention and control and their limitations, and, further, introduce next-generation algicidal technologies for the emergency protection of fish farms.

• Journal of Construction Engineering and Project Management
• /
• v.1 no.1
• /
• pp.37-43
• /
• 2011

Labor productivity is a significant factor associated with controlling time, cost, and quality. Many researchers have developed models to define methods of measuring the relationship between productivity and various parameters such as the size of working area, maximum working hours, and the crew composition. Most of the previous research has focused on estimating productivity; however, this research concentrates on estimating labor productivity and developing time and cost data for repetitive concrete pouring activity. In Korea, "Standard Estimating" only entails the average productivity data of the construction industry, and it is difficult to predict the time and cost spent on any particular project. As a result, errors occur in estimating duration and cost for individual activities or projects. To address these issues, this research sought to collect data, measure productivity, and develop time and cost data using labor productivity based on field conditions from the collected data. A probabilistic approach is also proposed to develop data. A case study is performed to validate this process using actual data collected from construction sites. It is possible that the result will be used as the EVMS baseline of cost management and schedule management.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.150-152
• /
• 1994

In this paper, the optimum shape design of stator slot of induction motors for iron loss reduction is proposed. To obtain the flux distribution in induction motors, 2-D finite element method with voltage source is employed. The iron loss is calculated from the iron loss data given by the iron manufacturer. To calculate the sensitivity of iron loss to shape variation, the sensitivity analysis of discrete approach is used. The proposed algorithm is applied to a 3-phase squirrel cage induction motor. The nodes at stator slot boundary of the induction motor are defined as design parameters. By controlling these parameters under the constant volume of iron, we can minimize the iron loss. Furthermore, the stator copper loss is reduced by increasing the slot area. So the stator slot area is determined at the point that the summation of iron loss and copper loss of stator is minimized. Since the constraint of constant volume of iron is nonlinear to the design parameters, the Gradient Projection method is used as an optimization algorithm.

• Nuclear Engineering and Technology
• /
• v.50 no.1
• /
• pp.97-106
• /
• 2018

Improved load-following capability is one of the most important technical tasks of a pressurized water reactor. Controlling the nuclear reactor core during load-following operation leads to some difficulties. These difficulties mainly arise from nuclear reactor core limitations in local power peaking: the core is subjected to sharp and large variation of local power density during transients. Axial offset (AO) is the parameter usually used to represent the core power peaking. One of the important local power peaking components in nuclear reactors is axial power peaking, which continuously changes. The main challenge of nuclear reactor control during load-following operation is to maintain the AO within acceptable limits, at a certain reference target value. This article proposes a new robust approach to AO control of pressurized water reactors during load-following operation. This method uses robust feedback-linearization control based on the multipoint kinetics reactor model (neutronic and thermal-hydraulic). In this model, the reactor core is divided into four nodes along the reactor axis. Simulation results show that this method improves the reactor load-following capability in the presence of parameter uncertainty and disturbances and can use optimum control rod groups to maneuver with variable overlapping.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2007.04a
• /
• pp.151-156
• /
• 2007

Topology optimization has been widely used in many research areas due to its ability in providing intial designs for the problems with complex boundary conditions. This also has been useful in compliant mechanisms, but resulting layouts may not be immediately manufacturable because they usually consist of members with varying widths and shapes. Also, there occurs some numerical difficulties such as checkerboards or hinge patterns which result from 1-node connection, and intermediate values which make the manufacturing of the designed structure difficult. Though there are many remedies given to avoid this problems, they cannot be prevented. One may avoid this difficulty by employing uniform ground beams and explicit hinge joints. The proposed method is to connect uniform ground beams with elastic short-beam hinge joints. By choosing the widths of short beams as design variables, dominant deformations can occur mainly by flexible joints having intermediate widths. Unlike the conventional methods used for compliance minimization, intermediate widths must appear in compliant mechanism design problems. Also, the present approach does not encounter the problem of one-point hinges.

• Proceedings of the Korea Technology Innovation Society Conference
• /
• 2001.05a
• /
• pp.411-430
• /
• 2001

This Paper analyses characteristics of the numerical controller industry in market formation and the flow of information between users and producers and the characteristic of knowledge base of the industry and discusses the difficulties derived, from the characteristics, in accumulation of technological capability In market formation between users and producers, the multi-layered market is not favorable to domestic producers in that lower end market is not large enough to provide cradle market to them which produce inferior quality and lower price than imported products. The credibility of the performance of a product is difficult to prove until a critical mass of products are sold. Therefore gaining market share is deterred by unproven credibility of the performance of the product. The flow of information between users and producers is limited. The flow of information on users environment through mass market to producers is essential for improving credibility of a product. The nature of knowledge base is tacit and the means of knowledge transmission is limited. Technological licensing and reverse engineering, which have been conventional means of knowledge transmission, are not useful in the numerical controller industry. These characteristics provide conditions of vicious circle in accumulation of technological capability of the numerical controller industry. It is conjectured that these characteristics are derived from the fact that the numerical controller is the result of IT based technological convergence in controlling machining process. This paper argues that these characteristics of the industry challenges existing approach to R&D management and framework of science and technology Policy.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.12
• /
• pp.1756-1763
• /
• 2010

Pasteurella multocida serogroup D strain, which produces P. multocida toxin (PMT), is a widespread and harmful pathogen of respiratory diseases such as pneumonia and progressive atrophic rhinitis (PAR) in swine. Vaccination has been considered the most desirable and effective approach for controlling the diseases caused by toxigenic P. multocida. To investigate the antigenicity and immunogenicity of partial fragments of recombinant PMT, recombinant proteins of the N-terminal (PMT-A), middle (PMT-B), C-terminal (PMT-C), and middle-C-terminal (PMT2.3) regions of PMT were successfully produced in an Escherichia coli expression system. The molecular masses of PMT-A, PMT-B, PMT-C, and PMT2.3 were ca. 53, 55, 35, and 84 kDa, respectively, purified by nickel-nitrilotriacetic acid (Ni-NTA) affinity column chromatography. All the recombinant proteins except for PMT-A showed immune responses to antisera obtained from a swine showing symptoms of PAR. Moreover, high titers of PMT-specific antibodies were raised from mice immunized with each of the recombinant proteins; however, the immunoreactivities of the antibodies to authentic PMT and heat-inactivated whole bacteria were different, respectively. In the protection study, the highest protection against homologous challenge was shown in the case of PMT2.3; relatively poor protections occurred for the other PMT fragments.