• Journal of Internet Computing and Services
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• v.17 no.6
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• pp.53-59
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• 2016

Recently, huge stream data have been generated in real time from various applications such as wireless sensor networks, Internet of Things services, and social network services. For this reason, to develop an efficient method have become one of significant issues in order to discover useful information from such data by processing and analyzing them and employing the information for better decision making. Since stream data are generated continuously and rapidly, there is a need to deal with them through the minimum access. In addition, an appropriate method is required to analyze stream data in resource limited environments where fast processing with low power consumption is necessary. To address this issue, the sliding window model has been proposed and researched. Meanwhile, one of data mining techniques for finding meaningful information from huge data, pattern mining extracts such information in pattern forms. Frequency-based traditional pattern mining can process only binary databases and treats items in the databases with the same importance. As a result, frequent pattern mining has a disadvantage that cannot reflect characteristics of real databases although it has played an essential role in the data mining field. From this aspect, high utility pattern mining has suggested for discovering more meaningful information from non-binary databases with the consideration of the characteristics and relative importance of items. General high utility pattern mining methods for static databases, however, are not suitable for handling stream data. To address this issue, sliding window based high utility pattern mining has been proposed for finding significant information from stream data in resource limited environments by considering their characteristics and processing them efficiently. In this paper, we conduct various experiments with datasets for performance evaluation of sliding window based high utility pattern mining algorithms and analyze experimental results, through which we study their characteristics and direction of improvement.

• Journal of Intelligence and Information Systems
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• v.13 no.1
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• pp.91-105
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• 2007

This research suggests a recommendation system that enables bidirectional communications between the user and system using a utility range-based product recommendation algorithm in order to provide more dynamic and personalized recommendations. The main idea of the proposed algorithm is to find the utility ranges of products based on user specified preference information and calculate the similarity by using overlapping probability of two range values. Based on the probability, we determine what products are similar to each other among the products in the product list of collaborative companies. We have also developed a Web-based application system to recommend similar products to the customer. Using the system, we carry out the experiments for the performance evaluation of the procedure. The experimental study shows that the utility range-based approach is a viable solution to the similar product recommendation problems from the viewpoint of both accuracy and satisfaction rate.

• The Journal of the Acoustical Society of Korea
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• v.42 no.4
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• pp.298-303
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• 2023

This study aimed to investigate the clinical utility of voiced sentence tasks for voice evaluation. To this end, we analyzed the correlation between perturbation-based acoustic measurements [jitter percent (jitter), shimmer percent (shimmer), Noise to Harmonic Ratio (NHR)] using sustained vowel phonation, and cepstrum-based acoustic measurements [Cepstral Peak Prominence (CPP), Low/High spectral ratio (L/H ratio)] using voiced sentences. As a result of analyzing data collected from 65 patients with voice disorders, there was a significant correlation between the CPP and jitter (r = -.624, p = .000), shimmer (r = -.530, p = .000), NHR (r = -.469, p = .000).This suggests that the cepstrum measurement of voiced sentences can be used as an alternative to the analysis limitations of the pathological voice such as not possible perturbation-based acoustic measurement, and result difference according to the analysis section.

• Asia Marketing Journal
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• v.18 no.3
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• pp.47-63
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• 2016

Rational choice theory holds that the alternative with largest expected utility in the choice set should always be chosen. However, it is often observed that an alternative with the largest expected utility is not always chosen while the choice task itself being avoided. Such a choice phenomenon cannot be explained by the traditional expected utility maximization principle. The current study posits shows that such a phenomenon can be attributed to the gap between the expected perceived gain (or loss) and the expected perceived value. This study mathematically analyses the relationship between the expectation of an alternative's gains or losses over the reference point and its expected value, when the perceived gains or losses follow continuous probability distributions. The proposed expected value (EV) function can explain the effects of loss aversion and uncertainty on the evaluation of an alternative based on the prospect theory value function. The proposed function reveals why the expected gain of an alternative should exceed some positive threshold in order for the alternative to be chosen. The model also explains why none of the two equally or similarly attractive options is chosen when they are presented together, but either of them is chosen when presented alone. The EV function and EG-EV curve can extract and visualize the core tenets of the prospect theory more clearly than the value function itself.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.1
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• pp.59-69
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• 1998

This research was conducted to suggest some directions for desirable urban green space planning through 1) establishing a new classification system by examining the existing concept, problems and characteristics of green space and 2) defining the essence of green space environment and finding some analytical and evaluative methods through a clear establishment of functions, indicators of green space. An analytical technique of green space, in which the coexistent relationship of human and other organisms was emphasized, was tried in order to realize urban green space planning. Based on the relevancy between green space and human being, green space was classified into green space for existence green space for utility, green space for both of existence and utility. The ratio of green covered, the ratio of greenery within the frame of vision, and the ratio of green volume in green space for existence was used as analytic and evaluative indicators.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.1
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• pp.73-87
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• 2016

Combining power generation and water production by desalination is economically advantageous. Most desalination projects use fossil fuels as an energy source, and thus contribute to increased levels of greenhouse gases. Environmental concerns have spurred researchers to find new sources of energy for desalination plants. The coupling of nuclear power production with desalination is one of the best options to achieve growth with lower environmental impact. In this paper, we will per-form a sensitivity study of coupling nuclear power to various combinations of desalination technology: {1} thermal (MSF [Multi-Stage Flashing], MED [Multi-Effect Distillation], and MED-TVC [Multi-Effect Distillation with Thermal Vapour Compression]); {2} membrane RO [Reverse Osmosis]; and {3} hybrid (MSF-RO [Multi-Stage Flashing & Reverse Osmosis] and MED-RO [Multi-Effect Distillation & Reverse Osmosis]). The Korean designed reactor plant, the APR1400 will be modeled as the energy production facility. The economical evaluation will then be executed using the computer program DEEP (Desalination Economic Evaluation Program) as developed by the IAEA. The program has capabilities to model several types of nuclear and fossil power plants, nuclear and fossil heat sources, and thermal distillation and membrane desalination technologies. The output of DEEP includes levelized water and power costs, breakdowns of cost components, energy consumption, and net saleable power for any selected option. In this study, we will examine the APR1400 coupled with a desalination power plant in the Kingdom of Saudi Arabia (KSA) as a prototypical example. The KSA currently has approximately 20% of the installed worldwide capacity for seawater desalination. Utilities such as power and water are constructed and run by the government. Per state practice, economic evaluation for these utilities do not consider or apply interest or carrying cost. Therefore, in this paper the evaluation results will be based on two scenarios. The first one assumes the water utility is under direct government control and in this case the interest and discount rate will be set to zero. The second scenario will assume that the water utility is controlled by a private enterprise and in this case we will consider different values of interest and discount rates (4%, 8%, & 12%).

• International Journal of Automotive Technology
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• v.5 no.2
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• pp.115-122
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• 2004

Evaluation of active safety control systems usually relies heavily on field testing and is time-consuming and costly. Advances in computer simulations make it possible to perform exhaustive design trials and evaluations before field testing, and promise to dramatically reduce development cost and cycle time. In this paper, a comprehensive simulation-based evaluation procedure is proposed, which combines standard evaluation maneuvers, worst-case techniques, and a driver model for closed-loop path following evaluations. A vehicle dynamic controller (VDC) for a popular Sport Utility Vehicle is evaluated using the proposed procedure. Simulation results show that the proposed procedure can be used to assess the performance of the VDC under various conditions and provides valuable information for the re-design of the VDC.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.505-512
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• 2022

In this study, a 3D printed assistive device was applied to X-ray examinations to diagnose human diseases. Based on the results of evaluating the device, statistical and regression analyses were conducted to evaluate its clinical utility and purchase intention, respectively. In the experiment, 90 radiologists performed X-ray examinations on patients who agreed with the use of the assistive device in oblique view X-rays of the lumbar spine, and then statistical analyses were undertaken with a traditional aid and factor analysis. The non-standardized coefficient values of the multiple regression analysis performed by setting the purchase intention of the 3D printed device as the dependent variable and the 3D printed device and traditional aid calculated by factor analysis as independent variables were 0.893 (p<0.001) and 0.269 (p<0.001), indicating statistically significant results. The results show that the 3D printed assistive device proposed in this study has higher clinical utility than traditional aids used in oblique view X-rays of the lumbar spine.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.103-117
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• 2006

This study develops an agent-based simulation model to evaluate tourist information systems under ubiquitous environment. In this study, individual tourist's activity chaining behavior is formulated as a utility maximization problem. The underlying assumption of the model is that tourists increase their activities within their time and budget constraints to maximize their utilities. The model seeks individual's optimal tour schedule by solving Prize-Collecting Multiple-Day Traveling Salesman Problem(PC MD TSP). The simulation-based evaluation framework allows investigating individual utility gains by their information type and the total expenditure at each tour attractions. The real-time tour activity scheduling system enables tourists to optimize their tour activities by minimizing their time loss and maximizing their opportunity to use high utility facilities.

• Journal of Society of Preventive Korean Medicine
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• v.16 no.3
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• pp.15-26
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• 2012

Objective : Only a few studies have investigated the life expectance and health related quality of life (HRQOL) about stroke patients. The purpose of this study is to analyze the life expectancy, preference based quality of life(QOL) and quality adjusted life years(QALYs) of stroke patients. Methods : We used data of 10,533 adults from 4th Korean national health and nutritional examination survey 2009 for evaluating HRQOL of stroke patients. We also analyzed the life expectancy for stroke patients using life table from national public health data. Finally we calculated the QALYs with and without stroke conditions and assumed the difference of QALYs. Results : The mean age of stroke patients was assumed to be 65. Lower income and less educated groups were prone to be exposed to the stroke conditions. Common comorbidities of stroke patients were ischemic heart attack, hypertension, diabetes and hyperlipidemia. The proportions of participants who reported problems in each of the five EQ-5D dimensions increased significantly at chronic stroke group. Participants with chronic stroke conditions had an almost 6-fold higher risk of impaired health utility(the lowest quartile of EQ-5D utility score) compared with non stroke participants, after adjustment of age, gender, income, education, comorbidity variables. The differences of life expectancy and QALYs between non-stroke and stroke group from the age of 65 till death were assumed to be 0.767 year and 3.103 QALYs. Conclusions : Although the authors analyzed the affecting factors of QOL and assumed the differences of life expectance and QALYs about stroke patients using domestic national data and statistic references, well designed cohort studies should be needed to prove the causal effects of affecting factors and to assume more correct QALY differences.