• Journal of Korean Society of Forest Science
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• v.87 no.2
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• pp.211-219
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• 1998

The major purpose of this study was to analyze the observance of attributes influencing on park visitors' experiences. The Importance-Performance technique has been commonly used to evaluate the importance of various recreation programs and management. In this study, the Importance-Performance technique was adopted to present a new approach called Observance-Influence Analysis. During the summer of 1996, 550 Worak-san National Park visitors were surveyed. The results of this study indicated that physical and biological attributes such as clear water, clean air, and beautiful valley, etc. were highly observed by visitors and those also highly influenced on visitors' experiences. Based on the respondents' rating to the attributes, action grid was formulated to suggest management actions. As mentioned before, attributes such as clear water, clean air, and beautiful valley were recognized as attributes needed concentrate efforts. Attributes related to forests such as diverse plants and trees, well maintained forests, etc. were also suggested as potential concerned attributes. However attributes related to services did not influenced highly on the visitors' experiences.

• Journal of the korean society of oceanography
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• v.39 no.1
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• pp.72-95
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• 2004

The Yellow Sea is characterized by relatively shallow water depth, varying range of tidal action and very complex coastal geometry such as islands, bays, peninsulas, tidal flats, shoals etc. The dynamic system is controlled by tides, regional winds, river discharge, and interaction with the Kuroshio. The circulation, water mass properties and their variability in the Yellow Sea are very complicated and still far from clear understanding. In this study, an effort to improve our understanding the dynamic feature of the Yellow Sea system was conducted using numerical simulation with the ROMS model, applying climatologic forcing such as winds, heat flux and fresh water precipitation. The inter-annual variability of general circulation and thermohaline structure throughout the year has been obtained, which has been compared with observational data sets. The simulated horizontal distribution and vertical cross-sectional structures of temperature and salinity show a good agreement with the observational data indicating significantly the water masses such as Yellow Sea Warm Water, Yellow Sea Bottom Cold Water, Changjiang River Diluted Water and other sporadically observed coastal waters around the Yellow Sea. The tidal effects on circulation and dynamic features such as coastal tidal fronts and coastal mixing are predominant in the Yellow Sea. Hence the tidal effects on those dynamic features are dealt in the accompanying paper (Kim et at., 2004). The ROMS model adopts curvilinear grid with horizontal resolution of 35 km and 20 vertical grid spacing confirming to relatively realistic bottom topography. The model was initialized with the LEVITUS climatologic data and forced by the monthly mean air-sea fluxes of momentum, heat and fresh water derived from COADS. On the open boundaries, climatological temperature and salinity are nudged every 20 days for data assimilation to stabilize the modeling implementation. This study demonstrates a Yellow Sea version of Atlantic Basin experiment conducted by Haidvogel et al. (2000) experiment that the ROMS simulates the dynamic variability of temperature, salinity, and velocity fields in the ocean. However the present study has been improved to deal with the large river system, open boundary nudging process and further with combination of the tidal forcing that is a significant feature in the Yellow Sea.

• Safety and Health at Work
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• v.9 no.3
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• pp.265-276
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• 2018

Background: Resilience engineering is a paradigm for safety management that focuses on coping with complexity to achieve success, even considering several conflicting goals. Modern sociotechnical systems have to be resilient to comply with the variability of everyday activities, the tight-coupled and under-specified nature of work, and the nonlinear interactions among agents. At organizational level, resilience can be described as a combination of four cornerstones: monitoring, responding, learning, and anticipating. Methods: Starting from these four categories, this article aims at defining a semiquantitative analytic framework to measure organizational resilience in complex sociotechnical systems, combining the resilience analysis grid and the analytic hierarchy process. Results: This article presents an approach for defining resilience abilities of an organization, creating a structured domain-dependent framework to define a resilience profile at different levels of abstraction, and identifying weaknesses and strengths of the system and potential actions to increase system's adaptive capacity. An illustrative example in an anesthesia department clarifies the outcomes of the approach. Conclusion: The outcome of the resilience analysis grid, i.e., a weighed set of probing questions, can be used in different domains, as a support tool in a wider Safety-II oriented managerial action to bring safety management into the core business of the organization.

• Journal of Practical Engineering Education
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• v.14 no.1
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• pp.219-224
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• 2022

Q-Learning is a technique widely used as a basic algorithm for reinforcement learning. Q-Learning trains the agent in the direction of maximizing the reward through the greedy action that selects the largest value among the rewards of the actions that can be taken in the current state. In this paper, we studied a policy that can speed up agent training using Q-Learning in Frozen Lake 8×8 grid environment. In addition, the training results of the existing algorithm of Q-learning and the algorithm that gave the attribute 'direction' to agent movement were compared. As a result, it was analyzed that the Q-Learning policy proposed in this paper can significantly increase both the accuracy and training speed compared to the general algorithm.

• The Journal of the Korean dental association
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• v.50 no.1
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• pp.22-30
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• 2012

The methods for the occlusal force measurement have long been developed. The occlusal analyzing equipment utilizing the pressure-sensitive film (Prescale) is useful for the assessment and comparison among large group of patients. On the other hand, the apparatus which uses the grid-based sensor sheet (T-scan) can be a useful assistant for acquiring the well-balanced occlusion. The device that can process the electrical input from the strain gauge which is attached to the tooth surface can collect the dynamic data of actual masticatory force. This device has been developed for the measurement of actual mastication with the food bolus and it can be a useful method for the comparison before and after the restorative treatment. Occlusal force measurement can be applied for the analysis of therapeutic action, diagnosis of crack- tooth syndrome, temporomandibul ar disease, and idiopathic implant loosening.

• Journal of the Korean housing association
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• v.24 no.6
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• pp.103-110
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• 2013

The purpose of this study is to estimate the perception of elderly residents on the residential environment improving projects and suggest the political implications. The survey include questionnaires about the importance and the satisfaction level on the project maintenance factors. The results were statistically analyzed by Importance-Performance Analysis (IPA). As the result of the study, firstly, it shows that 'the possible overkill area' on the IPA action grid includes none of factors except 'landscape' which is very similar to mean of performance score. the result of analysis means that the project is very efficient. Secondly, the policy is necessary to improve 'pedestrian passage', 'public open space' and 'transportation environment'. Considering elderly residents especially 'pedestrian passage' and 'public open space' are in need of improvement immediately. In detail 'traffic facility', building 'urban park' and 'pedestrian passage', 'paving of pedestrian passage', 'children's playground' are in need of improvement as well. The results of analysis on elderly and non-elderly residents of Yonnam project may be important foundation for future strategies for improvement.

• Earthquakes and Structures
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• v.27 no.3
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• pp.177-189
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• 2024

Accurately predicting the failure modes of reinforced concrete (RC) columns is essential for structural design and assessment. In this study, the challenges of imbalanced datasets and complex feature selection in machine learning (ML) methods were addressed through an optimized ML approach. By combining feature selection and oversampling techniques, the prediction of seismic failure modes in rectangular RC columns was improved. Two feature selection methods were used to identify six input parameters. To tackle class imbalance, the Borderline-SMOTE1 algorithm was employed, enhancing the learning capabilities of the models for minority classes. Eight ML algorithms were trained and fine-tuned using k-fold shuffle split cross-validation and grid search. The results showed that the artificial neural network model achieved 96.77% accuracy, while k-nearest neighbor, support vector machine, and random forest models each achieved 95.16% accuracy. The balanced dataset led to significant improvements, particularly in predicting the flexure-shear failure mode, with accuracy increasing by 6%, recall by 8%, and F1 scores by 7%. The use of the Borderline-SMOTE1 algorithm significantly improved the recognition of samples at failure mode boundaries, enhancing the classification performance of models like k-nearest neighbor and decision tree, which are highly sensitive to data distribution and decision boundaries. This method effectively addressed class imbalance and selected relevant features without requiring complex simulations like traditional methods, proving applicable for discerning failure modes in various concrete members under seismic action.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.231-243
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• 2016

This study presents the applicability of two-dimensional (2D) flood inundation model by applying to real irrigation reservoir failure with limited available data. The study area is Sandae Reservoir placed in Gyeongju and downstream area of it and the reservoir was failured by piping in 2013. The breach hydrograph was estimated from one-dimensional (1D) hydrodynamic model and the discharge was employed for upstream boundary of 2D flood inundation model. Topography of study area was generated by integrating digital contour map and satellite data, and Cartesian grids with 3m resolution to consider geometry of building, road and public stadium were used for 2D flood inundation analysis. The model validation was carried out by comparing predictions with field survey data including reservoir breach outflow, flood extent, flood height and arrival time, and identifying rational ranges with allowed error. In addition, the applicability of 2D model is examined using different simulation conditions involving grid size, building and roughness coefficient. This study is expected to contributed to analysis of irrigation reservoirs were at risk of a failure and setting up Emergency Action Plan (EAP) against irrigation reservoir failure.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.39-43
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• 2009

In this paper, the flow characteristics of underfill material driven by capillary action between flip-chip and substrate were investigated. Also, the effects of viscosity level and dispensing point of underfill on flow characteristics were investigated. Flip chip package size was $5mm{\times}5mm{\times}0.65^tmm$, the diameter of solder bump was 100 ${\mu}m$, and the pitch was 150 ${\mu}m$. It was full grid area-array type with 1024 I/Os. The glass substrate was used and the gap between the chip and substrate was 50 ${\mu}m$. For the experimental study, three different underfills with different viscous properties($2000{\sim}3700$ cps), and two different types of dispensing methods(center dot and edge dot) were used. The flow characteristics and filling time of underfill were investigated by using CCD camera. The results show that the edge flow was faster than center flow due to the edge effect, which was caused by the resistance of solder bumps. In case of edge dot dispensing type, the filling time was faster due to the large edge effect, compared to center dot dispensing type. Also, it was found that the underfill flow was faster and the filling time decreased as the viscosity level of underfill was decreased.

• Journal of the Korean Society for Library and Information Science
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• v.19
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• pp.63-112
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• 1990

The environment of the modern library is changing rapidly with advancements in information technology, massive increse in information, and with the changing needs of users for information in order to keep up with developments in science and technology. The library should also be in a constant state of change in accordance with the changing environment. But the current situation is that library organizations in Korea do not show any change. Here arises the need to diagnose the health of these organization. Organizational innovations can be achieved either by change in the organizational structure or administrative methods or in personal attitudes. In making organizational innovations, however, it is not sufficient only to change the organizational structure or the administrative methods without changing personal attitudes. The purpose of this thesis is to diagnose the health of university library organizations in Korea and to suggest prescriptions based on the results of this diagnosis, by means of organization development theory. In this study, the action research model and the diagnostic model were developed for the health of university library organization in Korea. The action research model consisted of 3 steps: diagnosis, intervention and evaluation. The diagnostic model comprised diagnostic criterion and diagnostic indicators. The health of an organization was selected as the diagnostic criterion. Diagnostic indicators were divided into 3 levels: personal job-satisfaction at the individual level, cohesiveness at the group level, and the organizational climate at the organizational level. Both the interview and the questionaire were used as diagnostic methods. The questionaire form was designed according to the Likert typle 5-point scale. For the investigation, 10 university libraries were selected from the private universities in Seoul, and questionaire sheets were sent to their 156 librarians and responses were received from 116 persons. An interview was carried out with a selected chief of departments of the library concerned. The results of the diagnosis show that the average personal job­satisfaction was 3.57, the group cohesiveness was 3.15 and organizational climate was 2.93, and accordingly the comprehensive health indicator was 3.22. The health of university library organizations in Korea was generally on the decline at all 3 levels. In particular, the organizational climate was in a very weak state. Most problems concern dissatisfaction with personnel policy, communications and non-professionally qualified directors. As the prescriptions, the following was suggested: institutionalization of the staff meeting for resolving problems with communication, appointement of professional directors, performance appraisal, conferring faculty status for librarians, and a suggest system. And for the improvement of the organizational climate, managerial grid training was suggested as one of the educational strategies for organizational development.