• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.36 no.4
• /
• pp.116-122
• /
• 2013

This study develops a dynamic scheduling model for parallel machine scheduling problem based on genetic algorithm (GA). GA combined with discrete event simulation to minimize the makespan and verifies the effectiveness of the developed model. This research consists of two stages. In the first stage, work sequence will be generated using GA, and the second stage developed work schedule applied to a real work area to verify that it could be executed in real work environment and remove the overlapping work, which causes bottleneck and long lead time. If not, go back to the first stage and develop another schedule until satisfied. Small size problem was experimented and suggested a reasonable schedule within limited resources. As a result of this research, work efficiency is increased, cycle time is decreased, and due date is satisfied within existed resources.

• Smart Structures and Systems
• /
• v.21 no.4
• /
• pp.435-448
• /
• 2018

This paper reports the development of a theoretically rigorous method for permanent way engineers to assess the condition of railway ballast under a concrete sleeper with the potential to be extended to a smart system for long-term health monitoring of railway ballast. Owing to the uncertainties induced by the problems of modeling error and measurement noise, the Bayesian approach was followed in the development. After the selection of the most plausible model class for describing the damage status of the rail-sleeper-ballast system, Bayesian model updating is adopted to calculate the posterior PDF of the ballast stiffness at various regions under the sleeper. An obvious drop in ballast stiffness at a region under the sleeper is an evidence of ballast damage. In model updating, the model that can minimize the discrepancy between the measured and model-predicted modal parameters can be considered as the most probable model for calculating the posterior PDF under the Bayesian framework. To address the problems of non-uniqueness and local minima in the model updating process, a two-stage hybrid optimization method was developed. The modified evolutionary algorithm was developed in the first stage to identify the important regions in the parameter space and resulting in a set of initial trials for deterministic optimization to locate all most probable models in the second stage. The proposed methodology was numerically and experimentally verified. Using the identified model, a series of comprehensive numerical case studies was carried out to investigate the effects of data quantity and quality on the results of ballast damage detection. Difficulties to be overcome before the proposed method can be extended to a long-term ballast monitoring system are discussed in the conclusion.

• Journal of Korea Society of Industrial Information Systems
• /
• v.9 no.2
• /
• pp.23-31
• /
• 2004

This paper focuses on a boundary surface based ray casting. In general the boundary surface based ray casting is processed in two stages. The first stage finds boundary surfaces and stores them into buffers. The second stage calculates a distance from a viewpoint to the voxels of the interested area by projecting boundary surfaces on the view plane, and then starts to traverse a volume data space with the distance. Our approach differs from the general boundary surface based ray casting in processing the first stage of it. Contrast to the typical boundary surface based ray casting where all boundary surfaces of volume data are stored into buffers, they are projected on the planes aligned to the axis of volume data coordinates and these projected data are stored into 6 buffers. Such maneuver shortens time for ray casting, and reduces memory usage because it can be carried out independently from the amount of the volume data.

• Women's Health Nursing
• /
• v.7 no.4
• /
• pp.560-578
• /
• 2001

The purpose of this study was to develop prevention and educational programs for battered women. The first stage was to assess battered women's health status and health needs. The second stage was to develop prevention and educational programs to improve battered women's health. A survey research design was used to gather data from June-November 1999 by the counselor. Research sample was recruited from shelter and women's counseling centers in Seoul, Inchon, Chooncheon, Taejeon, and Jeoju. Trained counselors contacted 218 women, who agreed verbally to participate in the study. The researcher did a literature review and developed the tool used. We did ten pretests and three counselors checked the tool for content validity. The reliability and validity of the instrument were acceptable. The second stage of the research consisted of lay-professional groups discussing the abuse problems and possible solutions. Each group had five professionals (counsellor, nurse, minister, psychiatrist, social worker) and five women who have experienced battering from her husband in community. Result of the survey and two(lay persons and professionals) group discussions showed that victims need more assessment of physical, mental and spiritual needs. Victims were beaten more often during their pregnancies than at other times. Various kind of strategy were frequently utilized, but still the number of women abused and suicides committed increased. Both studies showed that the women experienced severe beating, that they felt powerless, that they need to understand that society abuser characteristics, that they lack a protection support system and that society lacks would an understanding of battered women. Based on the result of both studies, we developed model for prevention and education of battered women. This educational program will increase women s power to solve the abuse problems. The ultimate goal of the program is to develop a one-stop center to give wholistic approach care to women in abuse situations.

• Korean Institute of Interior Design Journal
• /
• v.19 no.3
• /
• pp.172-179
• /
• 2010

The Sydney Opera House is built on a peninsula of rock that juts out into Sydney Harbor. The site was once a landing place for ships. Utzon, Architect, designed the theatres for the Opera House to fit the shape. The two theatres were placed side by side so that they both had extensive harbor views. The Sydney Opera House is designed the foyers to take full advantage of these sights. Because the building would be seen from all sides, even from above, it was to be a piece of sculpture. The outside was as important as the inside. The audience enters from behind the stage and walks around to the foyers overlooking the harbour. The wing and backstage areas are small because of the way the foyers wrap around the theatre. The stage is made up of large platform lifts which provide the vertical movement for changing scenery. The sets come up from the workshops below stage. The flytower fits under the largest roof shell and doesn't break the skyline. The important elements are the podium, the shells and the reminders. The podium, the huge monolithic concrete structure, contains hundreds of rooms and nearly all the technical equipment. The podium is clad with pink granite slabs and seen from the water. This design eliminated a maze of fire escape stairs and, at the same time, gave people a wonderful view of the harbour. The egg shell is remarkably strong and express the form as the symbol of the site.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.13 no.12
• /
• pp.965-971
• /
• 2003

To reach high areal density, less track pitch is expected and more servo bandwidth is required. One approach to overcoming the problem is by using dual stage servo system. For this system. we have suggested new milliactuator based on the shear mode of piezoelectric elements to drive the head suspension assembly. In this paper, we introduce milliactuator and controller design method, PQ method. PQ method reduces the controller design problem for DISO (dual-input/single-output) systems to two standard controller design problems for SISO ( single-input/single-output) problems. The first part of PQ method directly addresses the issue of actuator output contribution, and the second part allows the use of traditional loop shaping to achieve the overall system performance. This paper shows how to employ the PQ method to meet aggressive close-loop performance specifications for a disk drive system with a VCM and piezoelectric milliactuator.

• Archives of Plastic Surgery
• /
• v.44 no.6
• /
• pp.530-538
• /
• 2017

Background A pharyngocutaneous fistula is a common and difficult-to-manage complication after head and neck reconstruction. It can lead to serious complications such as flap failure, carotid artery rupture, and pharyngeal stricture, and may require additional surgery. Previous radiotherapy, a low serum albumin level, and a higher T stage have been proposed as contributing factors. We aimed to clarify the risk factors for pharyngocutaneous fistula in patients who underwent flap reconstruction and to describe our experiences in treating pharyngocutaneous fistula. Methods Squamous cell carcinoma cases that underwent flap reconstruction after cancer resection from 1995 to 2013 were analyzed retrospectively. We investigated several significant clinical risk factors. The treatment modality was selected according to the size of the fistula and the state of the surrounding tissue, with options including conservative management, direct closure, flap surgery, and pharyngostoma formation. Results A total of 127 cases (18 with fistulae) were analyzed. A higher T stage (P=0.048) and tube-type reconstruction (P=0.007) increased fistula incidence; other factors did not show statistical significance (P>0.05). Two cases were treated with conservative management, 1 case with direct closure, 4 cases with immediate reconstruction using a pectoralis major musculocutaneous flap, and 11 cases with direct closure (4 cases) or additional flap surgery (7 cases) after pharyngostoma formation. Conclusions Pharyngocutaneous fistula requires global management from prevention to treatment. In cases of advanced-stage cancer and tube-type reconstruction, a more cautious approach should be employed. Once it occurs, an accurate diagnosis of the fistula and a thorough assessment of the surrounding tissue are necessary, and aggressive treatment should be implemented in order to ensure satisfactory long-term results.

• Journal of Genetic Medicine
• /
• v.8 no.1
• /
• pp.17-27
• /
• 2011

Pre-eclampsia is a major cause of maternal and perinatal mortality and morbidity worldwide, but remains unclear about the underlying disease mechanisms. Pre-eclampsia is currently believed to be a two-stage disease. The first stage involves shallow cytotrophoblast invasion of maternal spiral arteriole, resulting in placental insufficiency. The hypoxic placenta release soluble factors, cytokines, and trophoblastic debris into maternal circulation, which induce systemic endothelial damage and dysfunction. This cause the second stage of the disease: maternal syndrome. Epidemiological research has consistently demonstrated a familial predisposition to pre-eclampsia. Intensive research efforts have been made to discover susceptibility genes that will inform our understanding of the pathophysiology of preeclampsia and that may provide direction for therapeutic or preventative strategies. In this review, we summarize the current understanding of the role of genetic factors in the pathophysiology of pre-eclampsia and explain the molecular approach to search for genetic clues in pre-eclampsia.

• Journal of Preventive Medicine and Public Health
• /
• v.22 no.3 s.27
• /
• pp.380-388
• /
• 1989

To evaluate the costs of the hypertension screening program of the Korea Medical Insurance Corporation, the records of the screening examinations were used. The sample size was 49,983 of the 906,554 people insured by the Corporation and was obtained by two-stage stratification random sampling. The alternatives for efficiency of the screening program, which were divided into three categories : modification of the screening test package, application of other hypertension diagnostic criteria, and selective approach of tested groups by age, were evaluated according to the cost per patient detected. The results of this study were as follows In the hypertension screening system, the cost per patient detected was Won 30,883. The most nonsensitive test for hypertension detection was ophthalmoscopy, which was examined during the second stage of screening. If the ophthalmoscope examination was excluded, olny one person was not detected, which was 0.2% of detected persons, and the cost per patient detected decreased to Won 28,098. The most efficient modification of the screening test package was measurement of blood pressure through the first and second stages of screening. The cost per patient detected by this modification was Won 24,408. The application of other diagnostic critera, which were more restricted criteria, increased the cost per patient detected by 3.7%-6.7%. The cost per patient detected were Won 170,582 for persons less than 39 years old, Won 20,032 for persons 40 to 59 years old, and Won 8,675 for persons 60 years old and over. In conclusion, the best alternative suggested with respect to efficiency and practical application excluded the ophthalmoscope examination of second stage screening and restricted the target population to persons greater than 40 years old. The application of this alternative decreased 54.9% of the screening costs and the cost per patient detected was Won 15,222. This study was limited in that measurement of effectivenes was not of the ultimate goal of screening, which is decreasing morbidity and mortality, but was of disease detection as the short-term objective.

• Archives of Plastic Surgery
• /
• v.49 no.1
• /
• pp.70-75
• /
• 2022

Background Fingertip injuries are very common; however, the reconstruction of volar pulp defects with nail bed defects is challenging in the absence of the amputated segment. We reconstructed fingertip amputations with nail bed defects using a new surgical approach: a subcutaneous flap and composite graft. Methods We treated 10 fingertip amputation patients without an amputated segment, with exposed distal phalangeal bone and full-thickness nail bed defects between February 2018 and December 2020. All patients underwent two-stage surgery: in the first stage, a subcutaneous flap was performed to cover the exposed distal phalanx, and in the second stage, a composite graft, consisting of nail bed, hyponychium, and volar pulp skin, was applied over the subcutaneous flap. Results All flaps survived and all composite grafts were successful. The wounds healed without any significant complications, including the donor site. The average follow-up duration was 11.2 months (range, 3-27 months). The new nail and the shape of the volar pulp were evaluated during follow-up. All patients were satisfied with their natural fingertip shapes and the new nails did not have any serious deformities. Conclusions A subcutaneous flap in combination with a composite graft fitting the shape of the defect could be another option for fingertip injuries without amputated segments.