• Journal of the Korean GEO-environmental Society
• /
• v.19 no.9
• /
• pp.13-19
• /
• 2018

Recently, there have been various problems aroused on the domestic infrastructures as the domestic cities become old. Accordingly, the national concerns grow on the urban railway and the related structures, which brings the national interests are brought on the research on the maintenance and rehabilitation of the old infrastructures. The underground structure of urban railway are checked with the strain gages or fiber brag grating (FBG) sensors on the railway. However, these methods are known to have resolution limitations on the investigations of the specified abnormal section. Therefore, the applicability of the Brillouin Optical Correlation Domain Analysis (BOCDA) based distributed fiber optic sensor system on the railway was evaluated in this study. The constructed BOCDA fiber optic sensor system shows high resolution of 10, 20, 50, 100 cm and capability of continuous monitoring on overall or specified section within 2 km range. The applicability evaluation was performed on the 250 m distribution of fiber optic sensors abandoned railway for continuous monitoring. The applicability of the system on the specified area was evaluated with wheel load testing. As a result, data loss tends to increase with the reduction of spatial resolution from 1.0 m to 0.1 m. Even though the measuring speed is reduced with lower spatial resolution, data accuracy increases on the location and deformation. The system can be applicable to various structures if the proper distribution method is invented later.

• Journal of Korea Port Economic Association
• /
• v.30 no.4
• /
• pp.47-67
• /
• 2014

This study examined elements which could evaluate a container terminal logistics system from the viewpoint of supply chain management. This study derived the elements of a container terminal logistics system such as flexibility, reliability, responsiveness, and information sharing and 16 evaluation sub-items in the aspect of a supply chain. In the result of analysis, the weight between SCM elements of a container terminal logistics system was the highest in reliability(0.282), followed by flexibility(0.273), responsiveness(0.224), and information sharing(0.221). The conversion weight was calculated by combining the weight of elements of a container terminal logistics system and the weight of evaluation sub-items. The highest weight which was considered as the most important factor to evaluate a container terminal logistics system was work planning(berth, yard) of flexibility(0.081), followed by accurate fulfillment of container work schedule(ship, yard) and the optimum distribution and arrangement of equipment(QC, TC, YT)(0.079), stable works without damage of containers and ships(0.071), and preventive maintenance of equipment and operators' skill(0.070).

• Journal of Wetlands Research
• /
• v.24 no.4
• /
• pp.256-267
• /
• 2022

This study analyzed the current status and trend of water quality using long-term water quality monitoring data measured over the past 5 years in the Seohwacheon Basin, located upstream of Daecheong Lake. In the Seohwacheon Basin, a project is underway to reduce the occurrence of algal blooms in the Daecheong Lake and to improve water quality, and continuous management is required for water quality management. The current water quality evaluation aims to identify the water quality management point, and the good water grade and the integrated water quality index (WQI) were used. For trend evaluation, the effect of the water quality improvement project was evaluated using the Mann-Kendall test and Sen's Slope. As a result of the evaluation, the current water quality index was used to identify the watersheds and when to manage water quality, and the effect of the improvement project was confirmed through trend analysis. Through this study, it is possible to review the water quality status and improvement effect using long-term water quality monitoring data, so it is expected to be applicable to similar types of watersheds in the future.

• Journal of Digital Convergence
• /
• v.13 no.10
• /
• pp.509-516
• /
• 2015

Intangibility, measurement difficulty and irreversibility, which are the characteristics of service, have such problems as obscurity and uncertainty in quality evaluation. Technical entrepreneurship education, a sort of public service, also contains such characteristics of service. To objectively evaluate the service quality of technical entrepreneurship education, this paper drew up factors as hierarchical structure, centered on FAHP technique, and conducted pre-processing, inputted those factors into triangular fuzzy number fuzzy judgement matrix, and calculated their weights. In this manner, this paper proposed a TESE system, through which an analysis can be conducted by drawing relative importance and priorities of the factors. The proposed system can efficiently evaluate the qualitative technical start-up education service quality factors quantitatively in the diversely changing technical start-up environment in view of the highest result quality (41%), which means performance in the relative importance of major factors. Namely, this paper confirmed that clear decision making can be made through an experiment.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.9 no.4
• /
• pp.351-358
• /
• 2016

Science and technology is developing rapidly as more powerful software with the rapid development of software testing and reliability assessment by the difficulty increases with the complexity of the software features of the larger increases NHPP software reliability models for failure analysis can have, in the literature, exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, finite failure NHPP models that assuming the expected value of the defect and infinite failures NHPP models that repairing software failure point in time reflects the situation, were presented for comparing property. Commonly used in the field of software reliability based on Erlang distribution software reliability model finite failures and infinite failures were presented for performance comparative evaluation problem. As a result, finite failure model is better than infinite failure model effectively. The parameters estimation using maximum likelihood estimation in the course of this study was conducted. As the results of this research, software developers to identify software failure property be able to help is concluded.

• Explosives and Blasting
• /
• v.36 no.3
• /
• pp.1-9
• /
• 2018

This study was conducted to evaluate the influences of the angle of artificial joints, the distance between the artificial joints and the blast hole, and the number of artificial joints on the pressure wave propagation, crack propagation, and blast wave velocity. The evaluation was conducted numerically by use of the Euler-Lagrange solver supported by the AUTODYN, which is a dynamic FEM program. As a result, it was found that the blast wave velocity was decreased most rapidly as either the distance between the artificial joint and the blast hole was decreased or the angle of the artificial joint was increased. In contrast to the case of no artificial joint, the amount of attenuation of the blast wave velocity was considerably large when an artificial joint was present. However, the effect of the number of artificial joint on the attenuation of the blast wave velocity was negligible under the given condition.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.17 no.3
• /
• pp.174-183
• /
• 1997

Turbine rotor disc consists of disc, bore, keyway, hub, and rim in which the typical defects are located. And these part of disc has very complicated geometry, therefore proper transducer selection, wedge design, fabrication, classification and evaluation of the signal identification are required. In this research, test block with the artificial flaws at keyway and boresurface parts have been used in order to establish the ultrasonic inspection technique for flaw detectability on disc. The analysis of the signals from the test blocks was performed. The wedges were designed according to the curvature from the discs. All the ultrasonic signals were collected and identified for evaluation. The ultrasonic inspection technique for the flaw-detection was established from this research. And it is proved that the result of this research can be applicable in the field inspection.

• Journal of Korean Neurosurgical Society
• /
• v.30 no.9
• /
• pp.1108-1114
• /
• 2001

Objective : Prognostic factors of metastatic brain tumors have been widely reported and their operative indications also have been extended gradually even to the poor grade patients. Authors intended to analyze the causative factors for the clinical outcome of metastatic brain tumors, especially with relevant to the poor prognosis by one year follow-up evaluation. Patients and Methods : The authors retrospectively studied the clinical characteristics of 46 cases(35 patients) with metastatic brain tumors among 466 cases(437 patients) which were operated on due to the brain tumor, during the period between January 1994 to June 1999. Statistical analysis was performed by using SPSS 8.0$^{(R)}$. A p-value of less than 0.05 was considered clinically significant. Result : Among the variable clinical factors in patients with metastatic brain tumors, Karnofsky Performance Scale (KPS) score of less than 70(16 patients), uncontrolled primary tumor(8 patients), and surgical resection without further adjuvant therapy(9 patients) showed statistically significant poor prognosis ; p value of 0.002, 0.032, and 0.001, respectively. Other tested variables, such as old age(greater than 65 years ; 10 patients), gender(male ; 20 patients), type of primary cancer(primary undefined ; 6 patients, lung cancer ; 15 patients), location(infratentorial ; 9 patients, sellar ; 5 patients), number of lesion(multiple ; 12 patients), and number of operation(multiple craniotomy ; 7 patients) were not related to the poor prognosis. Conclusions : The most common primary site of distant metastasis was lung. The poorer prognosis was highly correlated with various factors including low KPS score(<70), no postoperative adjuvant therapy, and uncontrolled primary tumors.

• Journal of Korea Water Resources Association
• /
• v.47 no.2
• /
• pp.195-206
• /
• 2014

In this study, a performance evaluation method of water supply for a multi-purpose dam based on deficitsupply method and reservoir storage is presented. The method is applied to 16 multi-purpose dams and water supply performance is evaluated. As a result, 6 dams (Soyanggang, Chungju, Hoengseong, Andong, Imha, and Hapcheon dam) have highest performance and 2 dams (Sumjingang and Buan dam) have relatively low performance. Particularly, Buan dam is the most vulnerable in the analysis results of reliability, resiliency, and vulnerability. Therefore, measures to improve the performance of water supply are needed in Buan multi-purpose dam.

• Journal of Technologic Dentistry
• /
• v.39 no.3
• /
• pp.137-143
• /
• 2017

Purpose: The purpose of this study is to analyze the fitness of heat - pressed ceramic laminate veneers fabricated using the additive manufacturing. Methods: Impression was replicated by using light body silicone and heavy body silicone on the custom tray, and it was fabricated using Type IV Stone. The test specimens were prepared by using a dental scanner, a laminating veneer using a dental design program, and a specimen with a 3D printer. The control specimens were prepared by the lost wax technique and heat - pressed to fabricate the specimens. The data of the specimens were measured by the RMS value of the internal fitness a using a 3-dimensional measurement program. Results: The Stereolithography laminate veneer group was measured at $78.10(4.09){\mu}m$ and the LWV group was measured at $31.50(5.10){\mu}m$. There is a significant difference between the two groups (p<0.001) Conclusion : Evaluation of fitness laminate veneers was fabricated by additive manufacturing showed the difference statistically significantly and clinically acceptable result.