• International conference on construction engineering and project management
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• 2013.01a
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• pp.509-512
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• 2013

An inappropriate space zoning plan causes the unnecessary transportation of construction material and equipment among work areas and increases the disorder of work space. Space zoning is an essential operation management technique which contributes to reduce the process and/or operation idle-time. This paper introduces a method that computes the idle-times between construction operations (or processes) by using Web-CYCLONE. It allows computing with idle-times that affect the construction productivity. Using the idle time between operations and between processes, it computes the optimal number of zones and finds the optimal combination of zones that minimize the idle times. The method contributes to minimize the idle times relative to the operation schedule using complete enumeration. This paper presents the system prototype in detail. A case study is presented to demonstrate the system and verifies the validity of the model. It allows a project manager to establish space zoning plan that effectively segregates a project into optimal number of construction zones and to assign the constrained resources (e.g., laborer, equipment).

• Journal of Chest Surgery
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• v.7 no.1
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• pp.85-92
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• 1974

During the years 1959 to 1974, 99 patients with patent ductus arteriosus were admitted to National University Hospital. These includes 5 patients with additional cardiovascular and 5 patients with severe pulmonary hypertension. All were operated upon except three refused operation. In all instances, the diagnosis was made by history and physical, roentgenological and electrographic examinations. In addition, in 53 patients, special diagnostic procedures were carried out either for diagnosis or for evaluation of pulmonary hypertension and associated cardiovascular anomalies. Right cardiac catheterization was resorted to in 51 patients. In one of these patients catheterization was incorrectly interpreted [ventricular septal defect]. Retrograde aortogram was performed in two patients. In both cases the ductus itself was visualized on the x-ray film. An additional vascular anomaly, namely the persistent left superior vena cava, was confirmed by retrograde angiogram in one of them. In 5 cases the pulmonary arterial pressure was elevated well over 80 mmHg. In these instances,the operative mortality was 80% [4 out of 5 patients]. The management of patent ductus arteriosus when associated with severe pulmonary hypertension. and/or other cardiac anomalies is controversial. Opinions differ as to how to close the ductus and to repair the cardiac anomalies as well as to whether a one-staged or two-staged procedure should be resorted to. The author is of the that each case must be evaluated individually before any specific surgical treatment is ou.tlined. The literature on the subject is reviewed in this paper.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.603-622
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• 2023

Human error (HE) is an important concern in safety-critical systems such as nuclear power plants (NPPs). HE has played a role in many accidents and outage incidents in NPPs. Despite the increased automation in NPPs, HE remains unavoidable. Hence, the need for HE detection is as important as HE prevention efforts. In NPPs, HE is rather rare. Hence, anomaly detection, a widely used machine learning technique for detecting rare anomalous instances, can be repurposed to detect potential HE. In this study, we develop an unsupervised anomaly detection technique based on generative adversarial networks (GANs) to detect anomalies in manually collected surveillance data in NPPs. More specifically, our GAN is trained to detect mismatches between automatically recorded sensor data and manually collected surveillance data, and hence, identify anomalous instances that can be attributed to HE. We test our GAN on both a real-world dataset and an external dataset obtained from a testbed, and we benchmark our results against state-of-the-art unsupervised anomaly detection algorithms, including one-class support vector machine and isolation forest. Our results show that the proposed GAN provides improved anomaly detection performance. Our study is promising for the future development of artificial intelligence based HE detection systems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.11a
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• pp.332-335
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• 2006

This paper considers a facility location problem, which is concerned with locating facilities on a supply chain network and installing the associated equipments at the facilities to meet a given set of demands. The objective function is to minimize the sum of setup cost (facility opening cost and equipment installation cost), operation cost, and distribution cost. For the equipments, various choices of equipment modes need to be determined. Moreover, in the problem, overwork is allowed each facility but at expensive operation cost. The proposed problem is characterized as being NP-hard problem, so that a heuristic algorithm is derived. In order to evaluate the performance of the proposed algorithm, computational experiments with various numerical instances are conducted.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.239-239
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• 2013

The peak klystron power for the PAL (Pohang Accelerator Laboratory) XFEL (X-ray Free Electron Laser) is up to 80 MW which is higher than that of PLS-II LINAC. To prevent the RF breakdown such a high power operation, some of RF components need to be redesigned to reduce the surface electric field gradient to be less than the breakdown gradient at the vacuum-metal surface. For instances, the redesign of the Stanford Linear Accelerator Energy Doubler (SLED) system, the directional coupler and 3dB power splitter using the finite-difference time-domain (FDTD) simulation will be presented.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.185-192
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• 2012

Line planning is to determine the frequency of trains on each line to satisfy origin-destination demand while minimizing total operation cost. However, different from the line planning in passenger transportation, it is more important at which intermediate stations each train should be stopped and shunted because the freight car handling works like drop-off or(and) pick-up can incur much time and high cost so that the delay deteriorates the quality of rail freight transportation service. We present an optimization model for constructing line plan in rail freight transportation to simultaneously minimize the train operation cost and total transportation time of freights. And we suggest a column generation approach for our problem, which can solve the real network instances in reasonable computation times.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2002.05a
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• pp.429-434
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• 2002

For companies assembling end products from sub assemblies or components, MRP (Material Requirement Planning) logic is frequently used to synchronize and pace the production activities for the required parts. However, in MRP, the planning of operational-level activities is left to short term scheduling. So, we need a good scheduling algorithm to generate feasible schedules taking into account shop floor characteristics and multi-level job structures used in MRP. In this paper, we present a GA (Genetic Algorithm) solution for this complex scheduling problem based on a new gene to reflect the machine assignment, operation sequences and the levels of the operations relative to final operation. The relative operation level is the control parameter that paces the completion timing of the components belonging to the same branch in the multi-level job hierarchy. In order to revise the fixed relative level which solutions are confined to, we apply large step transition in the first step and GA in the second step. We compare the genetic algorithm and 2-phase optimization with several dispatching rules in terms of tardiness for about forty modified standard job-shop problem instances.

• Industrial Engineering and Management Systems
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• v.15 no.1
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• pp.11-18
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• 2016

This paper considers a scheduling problem in a flexible job shop with a reconfigurable manufacturing cell. The flexible job shop has both operation and routing flexibilities, which can be represented in the form of a multiple process plan, i.e. each part can be processed through alternative operations, each of which can be processed on alternative machines. The scheduling problem has three decision variables: (a) selecting operation/machine pairs for each part; (b) sequencing of parts to be fed into the reconfigurable manufacturing cell; and (c) sequencing of the parts assigned to each machine. Due to the reconfigurable manufacturing cell's ability of adjusting the capacity, functionality and flexibility to the desired levels, the priority scheduling approach is proposed in which the three decisions are made at the same time by combining operation/machine selection rules, input sequencing rules and part sequencing rules. To show the performances of various rule combinations, simulation experiments were done on various instances generated randomly using the experiences of the manufacturing experts, and the results are reported for the objectives of minimizing makespan, mean flow time and mean tardiness, respectively.

• Journal of Trauma and Injury
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• v.20 no.2
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• pp.72-76
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• 2007

Purpose: The purpose of this clinical trial was to evaluate the fixation method for treating alveolar fractures in an emergency department. Methods: The efficiency of using the fixation method was judged on the basis of clinical criteria. Stability, occlusion state, bleeding amount after fixation, operation time, and difficulties during procedural operation were recorded. Results: Eight patients were enrolled in this study. In all instances, the fixation method was effective in bleeding control. Each patient had a noticeable decrement in bleeding. A wire was used for four of the eight patients, and nylon strings was used for the others. The average operation time was 6.3 minutes for the wire patients and 2.8 minutes for the Nylon string patients. No specific problem was identified during the procedural operation. However, the difference in the fixation material influenced the effectiveness of the procedure, the operation time, and the satisfaction of the doctor. Conclusion: In the emergency department, the fixation method using wire or nylon string in the treatment of alveolar fractures is effective in bleeding control

• The Journal of the Korea Contents Association
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• v.6 no.4
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• pp.19-28
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• 2006

XML instances for purpose of information exchange are normally stored in the legacy relational database. Therefore, integrations with relational database are required for effective XML applications. To support these requirements, virtual decomposition storage or decomposition storage methods which save separates structures of instances to relational database have researched. However, these storage methods contain different information of schema structure and layers which has caused difficulties to process query during search operation as well as increased overheads due to duplicate savings for separate storages. Therefore, in this research, additional field of 'Eltype' has introduced to previous database schema structure to instance and schema structure, provide consistent level information and propose storage structure to map each field to schema field of relational database. As results, XML instance and structures can be stored together to minimize overheads and required storage-space. Also, synchronized storage layer structure provides easier processing of search query.