• 한국경영과학회지
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• 제30권3호
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• pp.1-15
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• 2005

In our model, a fleet of vehicles start from docking point to collect loads at the terminals assigned to the point Then the docking points are connected to the hub by primary vehicle routes starting at the hub. This vehicle visit all the docking points to collect the loads which have been collected by the secondary vehicles. Our goal Is to minimize the long-run cost of setting up the docking Points and vehicle operation cost by deciding the location of the docking points and the routes optimally. We propose an heuristic algorithm to solve this and tested it though various experiments.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.83-86
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• 2003

Soil Aquifer Treatment (SAT) is a technique in which secondary- or tertiary-treated wastewater is infiltrated through unsaturated soil and stored in the saturated zone. In SAT, contaminants are removed by physical and biochemical reactions taking place in soils. In this study, a numerical model was developed to predict changes in water quality during SAT operations. The contaminant species considered in the model were ammonium, nitrate, dissolved organic carbon, and dissolved oxygen. The model was calibrated against experimental data obtained from one dimensional soil column tests conducted for 84 days. The calibrated model will be used to find out optimum conditions for the pilot- and regional-scale SAT operations to be scheduled for the next phase of this project.

• East Asian mathematical journal
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• 제26권2호
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• pp.179-190
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• 2010

We study the theoretical background on the relationship between the equality property and operations treated in different sub-areas in secondary school mathematics curriculum respectively studied. Furthermore, we discuss in detail the equality property in rational numbers field $\mathbb{Q}$ and the real numbers field $\mathbb{R}$. Through this study, professional knowledges of school teachers are enhanced so that these aforementioned knowledges are connected smoothly to teaching activities in classrooms.

• 한국과학교육학회지
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• 제9권1호
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• pp.75-89
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• 1989

Secondary schools in Korea have been faced with several critical problems with regard to science education. Among them one of the most fundamental problems is associated with laboratory-based science education. There fore as a part of research project for the improvement of science education in secondary schools, this study had its abjectives to inquire into the following areas related to laboratory experiment. ${\circ}$Survey and analysis of theoretical backgrounds for science teaching focused on laboratory experiments. ${\circ}$Status survey of experiment-based science teaching in high schools. ${\circ}$Development of model for improving experiment-based science teaching. In order to fulfill these objectives this study used methods of eiterature review, survey, and interviews. The major finding are as follows : ${\circ}$Some topic for laboratory experiments as oppeared in the textbooks are not appropriate in the light of sience curricular operations in high schools. ${\circ}$In some schools equipments and facilities of school laboratories are for from sufficiency. ${\circ}$Laboratory experiments are not financially supportel for ideal science teach in both middle schools and high schools. These are not on exhaustive list of findings from this study More finding and teaching model for improvement of science education are also described in this paper.

• Journal of Computing Science and Engineering
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• 제8권3호
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• pp.157-172
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• 2014

Contemporary embedded systems often use NAND flash memory instead of hard disks as their swap space of virtual memory. Since the read/write characteristics of NAND flash memory are very different from those of hard disks, an efficient page replacement algorithm is needed for this environment. Our analysis shows that temporal locality is dominant in virtual memory references but that is not the case for write references, when the read and write references are monitored separately. Based on this observation, we present a new page replacement algorithm that uses different strategies for read and write operations in predicting the re-reference likelihood of pages. For read operations, only temporal locality is used; but for write operations, both write frequency and temporal locality are used. The algorithm logically partitions the memory space into read and write areas to keep track of their reference patterns precisely, and then dynamically adjusts their size based on their reference patterns and I/O costs. Without requiring any external parameter to tune, the proposed algorithm outperforms CLOCK, CAR, and CFLRU by 20%-66%. It also supports optimized implementations for virtual memory systems.

• 대한두개안면성형외과학회지
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• 제19권1호
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• pp.13-19
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• 2018

Background: $Abb{\acute{e}}$ flap technique is one of the most challenging operations to correct horizontal deficiencies in secondary cleft lip deformity. Since its first introduction, the operative method was dynamically modified from simple variation to complete conceptual change, but conventional $Abb{\acute{e}}$ flap has many drawbacks in esthetic and functional aspect. Our purpose was reconstructing the symmetry of Cupid's bow and central vermilion tubercle with minimal sequalae. Methods: From 2008 to 2016, this technique was applied to 16 secondary cleft lip patients who had total or more than 60% of unilateral deficiency of Cupid's bow and central lip or tubercle pouting deficiency. A quadrangular-shaped flap was transferred from vermilion including skin and white line of central or contralateral lower lip. Pedicle division and insetting were made at 9 (unilateral) or 10 (bilateral) days after transfer. Secondary lip revision was done with open rhinoplasty after wound maturation. Results: Overall satisfaction was high with modified technique. Scar was minimally noticeable on both upper and lower lip especially. Balanced Cupid's bow and symmetric vermilion tubercle were made with relatively small size of flap compared to conventional $Abb{\acute{e}}$ flap. An accompanying benefit was reduced ectropion of lower lip, which made balanced upper and lower lip protrusion with more favorable profile. Conclusion: A new modified $Abb{\acute{e}}$ flap technique showed great satisfaction. It is worth considering in secondary cleft lip patient who has central lip shortage and asymmetry of upper lip vermilion border line. Our technique is one of the substitutes for correction of horizontal and central lip deficiency with asymmetric Cupid's bow.

• 한국산업융합학회 논문집
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• 제27권1호
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• pp.207-212
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• 2024

Recently, with the strengthening of environmental regulations, there has been an increasing interest in eco-friendly energy sources, leading to a trend of the increasing scale of Cargo Containment Systems (CCS) for Liquefied Natural Gas (LNG) carriers. Among these systems, membrane tanks have gained popularity in LNG transport vessels due to their superior spatial utilization and competitiveness. However, due to high initial investment costs and the difficulty in repair in case of damage, a safety layer, the secondary barrier, must be installed without fail. In this study, in order to apply a new secondary barrier to the existing membrane-type LNG CCS, tests were conducted on the fiberglass layer previously used in the Triplex-Flexible Secondary Barrier (FSB), substituting it with basalt fiber. Tensile and vertical tensile tests were performed to assess the newly applied material. Environmental tests were conducted at room temperature (25℃) and extremely low temperatures (-170℃), considering the temperatures to which substances may be exposed during LNG vessel operations. The basalt-FSB produced in this study demonstrated superior results compared to the specifications of the existing product, confirming its potential applicability for implementation.

• Archives of Plastic Surgery
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• 제41권5호
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• pp.535-541
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• 2014

Background Patients having unilateral breast reconstruction often require a second stage procedure on the contralateral breast to improve symmetry. In order to provide immediate symmetry and minimize the frequency and extent of secondary procedures, we began performing simultaneous contralateral balancing operations at the time of initial reconstruction. This study examines the indications, safety, and efficacy of this approach. Methods One-hundred and two consecutive breast reconstructions with simultaneous contralateral balancing procedures were identified. Data included patient age, body mass index (BMI), type of reconstruction and balancing procedure, specimen weight, transfusion requirement, complications and additional surgery under anesthesia. Unpaired t-tests were used to compare BMI, specimen weight and need for non-autologous transfusion. Results Average patient age was 48 years. The majority had autologous tissue-only reconstructions (94%) and the rest prosthesis-based reconstructions (6%). Balancing procedures included reduction mammoplasty (50%), mastopexy (49%), and augmentation mammoplasty (1%). Average BMI was 27 and average reduction specimen was 340 grams. Non-autologous blood transfusion rate was 9%. There was no relationship between BMI or reduction specimen weight and need for transfusion. We performed secondary surgery in 24% of the autologous group and 100% of the prosthesis group. Revision rate for symmetry was 13% in the autologous group and 17% in the prosthesis group. Conclusions Performing balancing at the time of breast reconstruction is safe and most effective in autologous reconstructions, where 87% did not require a second operation for symmetry.

• Journal of Gastric Cancer
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• 제10권4호
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• pp.234-240
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• 2010

Purpose: Most gastric cancer patients undergo operations at large tertiary hospitals in Korea. However, some patients are treated at low volume hospitals. We investigated patient outcomes after gastric surgery at a secondary hospital and compared with outcomes of large volume centers. Materials and Methods: We included 184 patients who underwent gastric surgery for gastric cancer at our hospital from January 2003 to December 2008. We conducted a retrospective study and evaluated the clinicopathological characteristics, clinical outcomes and survival rate of patients. Results: Mean age was 61.7 years old. Male to female ratio was 2.2 : 1. Proportion of early gastric cancer was 38.6% and that of advanced gastric cancer was 61.4%. The 5 year overall survival rate of 184 patients was 66.3%. The overall survival rate was significantly lower for people over 62 years old. The morbidity rate and mortality at our hospital were 10.3% and 0.5%, respectively. Conclusions: The overall survival rate, morbidity and mortality were similar to those of the previous reports from Korea. Treatment of gastric cancer at a secondary hospital is feasible and safe. Standardization of operations and management of gastric cancer patients of the Korean Gastric Cancer Association is the most important factor to achieve these outcomes.

• 대한두개안면성형외과학회지
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• 제15권3호
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• pp.133-137
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• 2014

Reconstruction of a full-thickness alar defect requires independent blood supplies to the inner and outer surfaces. Because of this, secondary operations are commonly needed for the division of skin flap from its origin. Here, we report a single-stage reconstruction of full-thickness alar defect, which was made possible by the use of a nasolabial island flap and septal mucosal hinge flap. A 49-year-old female had presented with a squamous cell carcinoma of the right ala which was invading through the mucosa. The lesion was excised with a 5-mm free margin through the full-thickness of ala. The lining and cartilage was restored using a septal mucosa hinge flap and a conchal cartilage from the ipsilateral ear. The superficial surface was covered with a nasolabial island flap based on a perforator from the angular artery. The three separate tissue layers were reconstructed as a single subunit, and no secondary operations were necessary. Single-stage reconstruction of the alar subunit was made possible by the use of a nasolabial island flap and septal mucosal hinge flap. Further studies are needed to compare long-term outcomes following single-stage and multi-stage reconstructions.