• Health Policy and Management
• /
• v.3 no.1
• /
• pp.102-123
• /
• 1993

This study investigates effcts of HMO internal structural arrangements on performance, specially cost reduction measured by hospitalization rate. This study formulates formalization, centralization measured by decision-making participation, differentiation, and coordination as structural factors, considering coordination as an intermediate factor between the rest of structural factors and hospitalization rate. The commonly used HMO types is assumed not effective in explaining performance differences. For the empirical test, I use bootstrap regression analyses with 48 HMOs. The results of the analyses show that HMO types fail to explain differences in hospitalization rate. However, dicision-making participation and differention effectively reduce hospiatalization rate, while frmalization increases hospitalization rate and coordination has nonessential effect on hospitalization rate. And, formalization and decision-making participation positively contribute to achieve coordination in HMO. These findings suggest that the theoretical framework derived from rational-citingency theory of formal organization better explains performance differences of HMOs than HMO types.

• Journal of Applied Reliability
• /
• v.17 no.4
• /
• pp.316-324
• /
• 2017

Purpose: The purpose of this study is to determine the replacement cycle applied age replacement policy by reliability analysis based on railway vehicle contactor's failure history data. Method: We performed reliability analysis based on railway vehicle contactor's failure history data. We found a suitable distribution by goodness of fit test and predicted the reliability through estimation of scale & shape parameter. Considering cost information we determined the replacement cycle that minimize the opportunity cost. Result: Suitable distribution was the Weibull and scale parameter & shape parameter are estimated by reliability analysis. The replacement cycle was predicted and MTTF, $B_6$ percentile life were suggested additionally. Conclusion: We confirmed that failure rate type of railway vehicle contactor is degradation model having a time dependent characteristic and examined the replacement cycle in our country's operating environment. We expect that this study result contribute to railway operation agency for maintenance policy decision.

• Journal of Positioning, Navigation, and Timing
• /
• v.7 no.4
• /
• pp.205-215
• /
• 2018

The recent emergence of new Global Navigation Satellite Systems (GNSS) has resulted in a gradual improvement in the performance of positioning services. This paper verifies the degree of improvement in positioning performance of Assisted-GNSS (A-GNSS) receivers using assistance information compared to standalone-GNSS receivers that do not use assistance information in various urban environments in Korea. For this purpose, field tests are performed in various urban and indoor environments in Korea. The assistance information is provided by u-blox's AssistNow Online and low-cost commercial receivers are used for mobile station receivers. Through experiments, the Time to First Fix (TTFF), acquisition sensitivity, and position accuracy performance improvement are analyzed. The results of the experiments show that using assistance data improved the performance in all experiment locations, and, in particular, a significant performance improvement in terms of TTFF.

• Journal of Auto-vehicle Safety Association
• /
• v.15 no.2
• /
• pp.49-55
• /
• 2023

In this study, it was analyzed that it is necessary to clarify the quality certification parts system, to make certification codes mandatory for self-certification products that are normally distributed, and to conduct follow-up management so that prompt action and thorough management of test reports are necessary in case of defects. Big data-based data, the detailed number of parts replacement cases, parts cost by part group, share, average labor cost, calculated to analyze the detailed automobile parts industry, and automobile parts certification system and automobile parts market in major countries including Korea and Through the distribution structure analysis, improvement plans for the automobile quality certification parts system were derived.

• Journal of Digestive Cancer Research
• /
• v.1 no.2
• /
• pp.73-77
• /
• 2013

Gastrointestinal (GI) cancers are top priorities for cancer control in Korea. In terms of epidemiological, population-health and economic burden, GI cancers such as stomach, liver and colorectal cancers have been top four cancers in the nation during the past decade and this trend is likely to continue in the near future. In order to reduce the great burden of GI cancer in Korea, the nation might need the following strategies: (1) to put more focus on primary prevention on infection/diet and related research; (2) to improve screening rates for colorectal and stomach cancers, and conduct more cost-effectiveness analysis of these screening programs, e.g., Fecal Occult Blood Test vs. colonoscopy; (3) to establish a more consistent and integrative cost-effectiveness analysis system for new cancer treatments and anticancer drugs; and (4) to place more emphasis on hospice and other palliative care of GI cancer, as well as on the etiology, staging and treatment of pancreas cancer with its poor survival rate.

• International Journal of Aerospace System Engineering
• /
• v.10 no.2
• /
• pp.1-4
• /
• 2023

Even though the recent development trend of wind turbine systems has been focused on larger MW Classes, the small-scale wind turbine system has been continuously developed because it has some advantages due to easy personnel establishment and use with low cost and energy saving effect. This work is to propose a specific structural design and analysis procedure for development of a low noise 500W class small wind turbine system which will be applicable to relatively low wind speed region like Korea. The proposed structural feature has a skin-spar-foam sandwich composite structure with the E-glass/Epoxy face sheets and the Urethane foam core for lightness, structural stability, low manufacturing cost and easy manufacturing process. Moreover this type of structure has good behaviors for reduction of vibration and noise. Structural analysis including load cases, stress, deformation, buckling and vibration was performed using the Finite Element Method. In order to evaluate the designed blade structure the structural tests were done, and their test results were compared with the estimated results.

• Journal of Sensor Science and Technology
• /
• v.33 no.5
• /
• pp.378-383
• /
• 2024

This study developed a buoyancy-based level sensor composed of a buoyant object, a sensing unit, and a signal generation unit to meet the demand of low-cost, high-efficiency inundation-detection sensors. The volume of the submerged buoyant object remained nearly constant even in the presence of water-level fluctuations, allowing stable water-level data acquisition. The measurement resolution and measurement repeatability were confirmed to be within 0.4 mm and 0.3%, respectively. LoRa-based communication was used to implement the IoT-based inundation-detection sensor. The measurement deviation between the sensors is approximately 0.15%. The unresponsive level at which measurement was not possible was confirmed to be approximately 2 mm. Excluding this unresponsive range, the water level measurements exhibited very high linearity, allowing precise measurements. Furthermore, a test bed was established in an inundation-vulnerable area using buoyancy-based level sensors.

• The KIPS Transactions:PartD
• /
• v.13D no.2 s.105
• /
• pp.215-222
• /
• 2006

The importance of mobile software test is being addressed to improve the productivity and reliability of the software. Test automation technique based on mobile platform is required for effective application of mobile software test. That is, a technique is needed to generate test case for mobile platform API. When test case generated, software productivity and reliability are improved, while test duration and cost are decreased. In this paper, we identified test case generation scope through previous works about test automation, suggested keyword driven method, a test case generation technique on J2ME platform, and recognized that proposed method can be applicable to generating test case based on J2ME platform.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.05a
• /
• pp.254-257
• /
• 2007

In this study, hydroformability and mechanical properties of pre- and post- heat treated Al6061 tubes at different extrusion type were investigated. For the investigation, as-extruded, full annealed and T6-treated Al 6061 tubes at different extrusion type were prepared. To evaluate the hydroformability, uni-axial tensile test and free bulge test were performed at room temperature and $200^{\circ}C$. Also mechanical properties of hydroformed part at various pre- and post-heat treatments were estimated by tensile test. And the tensile test specimens were obtained from hexagonal prototype hydroformed tube at $200^{\circ}C$. As for the heat treatment, hydroformability of full annealed tube is 25% higher than that of extruded tube. The tensile strength and elongation were more than 330MPa and 12%, respectively, when hydroformed part was post-T6 treated after hydroforming of pre- full annealed tube. However, hydroformed part using T6 pre treated tube represents high strength and low elongation, 8%. Therefore, the T6 treatment after hydroforming for as-extruded tube is cost-effective. Hydroformability of Al6061 tube showed similar value for both extrusion types. But flow stress of seam tube showed $20{\sim}50MPa$ lower value.

• Geomechanics and Engineering
• /
• v.9 no.4
• /
• pp.483-498
• /
• 2015

This article describes a new in-situ load test called the Hydraulic Cylinder Test (HCT) and its application to determine the geotechnical properties of soil-rock mixtures. The main advantages of the test are its easy implementation, speed of execution and low-cost. This article provides a detailed description of the equipment and the test procedure, and examines a case study of its application to determine the geotechnical properties of an earth-filled dam for a tailings pond. The containment dams of the ponds are made from blocks of gypsum and marl, obtained from the excavation of the ponds, mixed in a matrix of sands and clays. The size of the rocks varies between 1 and 30 cm. The HCT is particularly useful for determining the geotechnical properties of this type of soil-rock mixture. Nine HCTs were carried out to determine its strength (c, ${\phi}$) and deformation (B, G) properties. The results obtained were validated using the Bim strength criterion, recently proposed, and some pressure meter tests carried out beforehand. The properties obtained are used to analyze the stability of the dam using computer simulations and a modification to its design is proposed.