• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.109-134
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• 2018

Collaborative Filtering (CF) is widely used in recommendation field, which can be divided into rating-based CF and learning-to-rank based CF. Although many methods have been proposed based on these two kinds of CF, there still be room for improvement. Firstly, the data sparsity problem still remains a big challenge for CF algorithms. Secondly, the malicious rating given by some illegal users may affect the recommendation accuracy. Existing CF algorithms seldom took both of the two observations into consideration. In this paper, we propose a recommendation method based on listwise learning-to-rank by incorporating users' social information. By taking both ratings and order of items into consideration, the Plackett-Luce model is presented to find more accurate similar users. In order to alleviate the data sparsity problem, the improved matrix factorization model by integrating the influence of similar users is proposed to predict the rating. On the basis of exploring the trust relationship between users according to their social information, a listwise learning-to-rank algorithm is proposed to learn an optimal ranking model, which can output the recommendation list more consistent with the user preference. Comprehensive experiments conducted on two public real-world datasets show that our approach not only achieves high recommendation accuracy in relatively short runtime, but also is able to reduce the impact of malicious ratings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4B
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• pp.314-321
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• 2011

There have been considerable standardization works to measure subjective video quality. However, these standardization methods are based on the situation where they have original or reference video sequences, and measure the video quality by looking the sequence during short time duration, e.g. 10 seconds. Since people's TV watching time durations in IPTV services are very long (e.g. more than 30 minutes), the quality measurements by the standards are not practical. In this paper, we analyze the effect of video quality rating period to MOS (Mean Opinion Score), and suggest a proper rating duration of subjective video quality for IPTV services.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.550-557
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• 2009

The concepts of 'sustainable development', 'sustainable construction' and 'green building' have been elevated to priority levels in all types and phases of construction project development worldwide. Consultants and contractors are now required to seriously consider the impact of their operations on the natural environment and the society, and consequently adopt sustainable construction practices in the development process to minimize and mitigate the negative impacts of their activities. However, existing sustainability rating tools apply to the design, post-construction and operation phases of a building; no tool exists for the rating of the performance of the contractor or the project team at the construction phase. This study aimed to develop a model for evaluating the sustainability of construction operations, drawing on the global best practice standards on sustainability. Practical applications of the model were carried out through case studies to evaluate the performances of fifteen construction firms in New Zealand. The developed model and the outcomes of the case studies were presented, including potential areas of weaknesses, strengths, constraints to achievement or adoption of sustainable construction practices and areas for improvement in the operations of the firms. The successful application of the developed model in practice shows its usefulness and ease of application. It is therefore recommended for adoption as a simple but effective system for measuring and reporting on sustainability performance or sustainability of construction operations of firms in New Zealand and elsewhere.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.367-371
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• 2005

Social noise survey on multiple residential noises such as nut impact, air-borne, bathroom, drainage and traffic noises was conducted to investigate major variables affecting the overall satisfaction for noise environment The effect of individual noise perception on the evaluation of the overall noise environment was investigated through a questionnaire survey on annoyance, disturbance and noise sensitivity. Auditory experiments was also undertaken to determine noise level according to the percent of satisfaction for individual noise source. As a result of survey, it was found that satisfaction for floor impact noise most greatly affects the overall satisfaction for noise environment and annoyance most greatly affects the satisfaction for individual noise sources. Result of auditory experiment showed that the noise level of floor impact noise by bang machine, airborne, drainage and traffic noise corresponding to 50% satisfaction is 44dB($L_{i,Fmax,AW}$) and 40dBA, respectively.

• Asia Marketing Journal
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• v.25 no.1
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• pp.37-44
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• 2023

Firm innovativeness and financing capacity are critical signals to stakeholders as they are key drivers of firm performance and competitiveness and indicate the firm's ability to fund its operations and growth initiatives. Based on signaling theory, this study investigates the signaling effect of a firm's innovativeness and creditworthiness and examines its signaling effectiveness. Using Korean innovation data and Korea Investors Service financial data for nine years, the findings indicate that a firm's technological innovation has a negative impact on its credit ratings, while non-technological innovation has a positive impact. Furthermore, a firm's credit ratings positively impact its performance. The current study contributes to the literature on signaling theory by exploring the signaling effect of a firm's innovativeness and creditworthiness. The findings provide insights for managers on how to send and monitor signals to stakeholders.

• Korean Journal of Biological Psychiatry
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• v.4 no.1
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• pp.116-120
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• 1997

This study investigated the antidepressant efficacy and it's impact on the quality of life of depressed patients. We performed Hamilton Depression Rating Scale(HDRS), and Montgomery-Asberg Depression Rating Scale(MADRS), and Health-related Quality of Life Questionnaire(HQLQ) to both tricyclic antidepressant(TCA) and sertraline groups. There were 16 subjects in this study. The tricyclic group had 9 subjects and the sertraline group had 7. The TCA and sertraline produced a similar degree of response. Both groups experienced a reduction of 70% or more in mean HDRS and MADRS total score after 6wks. In HQLQ, the TCAs group also showed improved bed disability days, alertness behavior, and social interaction, the sertraline group showed improved health perception, alertness behavior, home management, and social interaction. We suggested that the improvement of "Quality of life" were not in proportion to the clinical symptom's improvement. Therefore, clinicians should consider the benefit of antidepressant treatment in terms of quality of life.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.31-34
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• 2001

The customer unsatisfaction in the new products exists, though the most of enterprises using QFD. It is mainly caused by the failure of corrective determination of technical importance rating(TIR). To derive the technical importance rating, the impact of the fulfillment of design requirements on the satisfaction of customer requirements must first be quantified. This has been accomplished through the use of a 1-3-9 or a 1-5-9 scale and ignored the peak of the house of quality(HOQ). In this paper we suggested the methodology reflecting effectiveness among engineering characteristics and adjusting the relationship strength between customer attribute(CA) and engineering characteristic (EC), by using limit probability and PCMR(pairwise comparison and median rank). With using this method, the determination of TIR would be more suitable for the voice of customers objectively. Here negative correlation is ignored.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1421-1424
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• 2006

Recently Requirement of indoor environment is increased in APT. Among indoor noises of APT, noise of plumbing system in bathroom is very serious problem except of floor impact noise. Plumbing system with wan hanging unit make a good grade and recognition in rating noise of bathroom in grade of house rating. But it is hard to find a data which are measured in APT built. In this study, the effect of noise reduction is checked by measuring the noise of plumbing system with wall hanging unit that is built. As result the upper household's Peak sound level is measured 80dB(A), the under household's peak sound level is measured 40dB(A).

• Nuclear Engineering and Technology
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• v.40 no.4
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• pp.251-254
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• 2008

Issues and themes concerned with nuclear power plant uprating are examined. Attention is brought to the fact that many candidate nuclear power plants for uprating have anyway been operated below their rated power for a significant part of their operating life. The key issues remain safety and reliability in operation at all times, irrespective of the nuclear power plant's chronological or design age or power rating. The effects of power uprates are discussed in terms of material aspects and expected demands on the systems, structures and components. The impact on operation and maintenance methods is indicated in terms of changes to the ageing surveillance programmes. Attention is brought to the necessity checking or revising operator actions after power up-rating has been implemented.

• International Journal of Advanced Culture Technology
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• v.12 no.2
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• pp.180-189
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• 2024

We aimed to see if approach-avoidance visual experience would have different effects in the valence rating of emojis. Previous literature has shown that approach-avoidance tendencies have influences people's emotional perceptions. Up until now, research on emojis have been heavily focused on static emojis, which gives room for exploration whether if movement added on to emoji would elicit different emotional responses. In the study, we examined the impact of approach-avoidance visual experience of emojis via mobile interface, categorized into 4 experimental conditions (positive approach, negative approach, positive avoid, and negative avoid), and conducted semi-structured interviews to identify users' reasonings towards their valence ratings on specific emojis with approach or avoid movements. We found that positive approach emojis were the highest valence rating and preferred by the participants, while there were no differences between negative emoji approach or avoidance. Based on these findings, we conclude that positive emojis could be intensified to be more positive with approach motion, yet for negative emojis, individual differences or contextual differences may arise in its emotional ratings.