• Korean Management Science Review
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• v.33 no.3
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• pp.19-30
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• 2016

This study provides a framework to assess network design under the regime of QoE (Quality of Experience). Our approach is expected to reveal the necessity of developing the QoE measures and applying this notion to network design, particularly in the mobile environment. Furthermore, our model shows the ample potential that both users and network providers are able to attain a win-win case by shifting the focus on network design and service operations from QoS (Quality of Service) to QoE. Since the former considers only relevant technological specifications, it may fail in capturing critical factors surrounding users, such as a context where the corresponding user is working on. For example, according to one study [13], the bit-rate, a widely employed QoS measure, shows inferior performance in provisioning network resources to the MOS (Mean Opinion Score), a representative QoE measure. Our framework develops the idea and construct a prototype to systematically assess network design and operations in terms of QoE. The proposed prototype aims at achieving a higher level of efficiency without severely deteriorating users' satisfaction level. We also provide some simulation results which support our idea. That is, reducing the chance of over-provisioning on the basis of the QoE paradigm results in a great flexibility. It may give price cut for users or postponement of network investment for providers or both. Our simulation results also seem robust irrespective of the forms of the QoS-QoE relationship.

• Journal of Korean Society for Quality Management
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• v.27 no.2
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• pp.126-142
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• 1999

Robust design is an approach to reducing performance variation of quality characteristic values in quality engineering. Taguchi has an idea that mean and variation are handled simultaneously to reduce the expected loss in products and processes. Taguchi parameter design has a great deal of advantages but it also has some disadvantages. The various research efforts aimed at developing alternative methods. In the Taguchi parameter design, the product-array approach using orthogonal arrays is mainly used. However, it often requires an excessive number of experiments. An alternative approach, which is called the combined-array approach, was suggested by Welch et. al. ( 1990) and studied by others. In these studies, only single quality characteristic was considered. In this paper we propose how to simultaneously optimize multiple quality characteristics using desirability function when we used the combined-array approach to assign control and noise factors. An example is illustrated to show the difference between the Taguchi's product-array approach and the combined-array approach.

• Journal of the Optical Society of Korea
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• v.18 no.3
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• pp.261-273
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• 2014

In this paper, metal insulator metal (MIM) plasmonic slot cavity narrow band-pass filters (NBPFs) are studied. The metal and dielectric of the structures are silver (Ag) and air, respectively. To improve the quality factor and attenuation range, two novel NBPFs based on tapered structures and double cavity systems are proposed and numerically analyzed by using the two-dimensional (2-D) finite difference time domain (FDTD) method. The impact of different parameters on the transmission spectrum is scrutinized. We have shown that increasing the cavities' lengths increases the resonance wavelength in a linear relationship, and also increases the quality factor, and simultaneously the attenuation of the wave transmitted through the cavities. Furthermore, increasing the slope of tapers of the input and output waveguides decreases attenuation of the wave transmitted through the waveguide, but simultaneously decreases the quality factor, hence there should be a trade-off between loss and quality factor. However, the idea of adding tapers to the waveguides' discontinuities of the simple structure helps us to improve the device total performance, such as quality factor for the single cavity and attenuation range for the double cavity. According to the proposed NBPFs, two, three, and four-port power splitters functioning at 1320 nm and novel ultra-compact two-wavelength and triple-wavelength demultiplexers in the range of 1300-1550 nm are proposed and the impacts of different parameters on their performances are numerically investigated. The idea of using tapered waveguides at the structure discontinuities facilitates the design of ultra-compact demultiplexers and splitters.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06c
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• pp.155-158
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• 1998

IMBE(Improved Multi-Band Excitation) vocoders exhibit good performance at low data rates. The major drawback to IMBE coders is their large computational requirements. In this paper, thus, we propose a new pitch search method that preserves the quality of the IMBE vocoder with reduced complexity. The basic idea is to reduce computation complexity of the pitch searching by using the SAMDF. Applying the proposed method to the IMBE vocoder, we can get approximately 52.02% searching time reduction in the pitch search. There is no difference in voice quality between conventional IMBE and proposed IMBE.

• Journal of Korean Society for Quality Management
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• v.19 no.2
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• pp.1-16
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• 1991

Recently, Cook and Weisberg(l989) presented dynamic graphics for regression diagnostics. They suggested animating graphics which could aid to understanding the effects of adding a variable to a model. In this paper, using the Cook and Weisberg's idea of animation, we propose a dynamic graphical method for residuals to display the effects of removing an observation from a model. Based on the information obtained from these animating graphics, it is possible to see the influence of outliers on influencial observations for regression diagnostics.

• Journal of the Korea Institute of Building Construction
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• v.5 no.3 s.17
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• pp.117-124
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• 2005

Quality management in construction industry becomes more significant under the existing conditions such as, increasing higher demand caused by the high value of real estate and extension of the warranty period. Therefore, this study presents the alternative idea related to the current quality management conditions of small and medium construction companies, including the difficulties and problems in qualify management, in order to develop the systematical method for the quality management in small and medium construction company.

• Journal of Korean Society for Quality Management
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• v.32 no.3
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• pp.81-93
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• 2004

There is no doubt that BSC(Balanced Scorecard), ABC(Activity-Based Costing System), EVA(Economic Value Added System) draw sensation in the world as the tools of Performance Evaluation System and Quality Control. They are useful tools that can help succeed in the dynamic and competitive business environment. These three tools are discussed respectably. However, it also brings doubt whether it is possible to integrate the three tools made in the similar time and which way is appropriate among the three tools according to the type and the circumstance of business. In fact, these tools are not the opposing relations but the complementary relations. Consequently, this paper explains the relations of the three methods and suggests the process of the integrated models. Besides, it provides an idea about when Performance Evaluation System and Quality Control are needed for companies under different aspects considering the circumstance used the respective methods individually.

• Korean Journal of Biological Psychiatry
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• v.24 no.4
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• pp.212-218
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• 2017

Objectives We aimed to examine whether mindfulness skills are mediating the improvements of depressive symptoms in patients with mood disorders who practiced Mindfulness-Based Cognitive Therapy (MBCT). Methods A total of 19 patients with mood disorder were included in this study. The participants were divided into two subgroups: a normal to mild depression group and a moderate depression group. The participants completed questionnaires to assess depressive symptoms, anxiety, quality of life, suicidal idea, and mindfulness skills which were measured by the Five Facets of Mindfulness Questionnaire (FFMQ) before and after MBCT course. Results The moderate depression group showed improvements through MBCT in depressive symptoms and suicidal idea, but not in anxiety and quality of life. The normal to mild depression group showed no significant change through MBCT. The improvement of depressive symptoms in the moderate depression group was predictable by improvements of the five facets of mindfulness, especially by 'observe' and 'non-react' components. Conclusions This study showed that currently depressive patients with moderate severity but not with normal to mild severity benefit from MBCT in reducing depressive symptoms and suicidal idea. The improvement of depressive symptoms was mediated by improved mindfulness skills through MBCT.

• The Journal of Information Systems
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• v.26 no.4
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• pp.1-15
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• 2017

Purpose Through the provision of real time performance information about who is contributing and who is not in Electronic Brainstorming, prior studies evidenced a significant performance gain. However, it has been observed that the quantity-based performance feedback alone does not have enough restrictiveness to guide the performance behavior throughout the idea generation session. We included the notion of goal setting into the process performance feedback mechanism in an effort to regulate performance behavior and to better understand why individuals in Electronic Brainstorming are not obtaining enough stimulation benefits in the group interaction process. Design/methodology/approach We had developed real-time visual process performance feedback and modified to include goal setting. This mechanism visually displays individuals' performances two-dimensionally (quality for each idea vertically and quantity of ideas horizontally along with their goals). As individuals' contributions accumulate, the mechanism reveals performance histories by connecting the sequence of ideas in a time-series format, telling stories of individuals' performances. Then, we compared the performance outcome from this study with the outcomes from two prior studies (i.e., Jung et al., 2010 and Jung, 2014). Findings The results showed that the inclusion of goal setting into the process performance feedback solved the issue in the previous study. That was the lower than expected magnitude of performance enhancement of process performance feedback when compared to that of quantity-based feedback. It appears that goals as a motivational technique provide standards for systematic self-evaluation, serving as a cue to regulate performance behavior by strengthening the linkage between effort and performance. Thus, goals seem to set up a self-fulfilling prophecy, preconditioning better performance. However, the outcome still showed that its performance magnitude is unsatisfactory because the outcome of this study turned out to be close to the outcome of just quantity-based performance feedback in Jung et al.'s (2010) study.

• Proceedings of the Korean Society for Quality Management Conference
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• 1998.11a
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• pp.37-42
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• 1998

In the 11th AQCS(1997), the paper entitled 'Statistical Analysis of Baseball Records - Jinx and National Characteristics -' was presented by the same authors. At that time, the differences between Japanese characteristics and those of Europeans, using baseball data were discussed, mainly from the viewpoint of 'ways of thinking about chance cause and assignable cause.' In this paper, the authors described also on the same subject from the different viewpoint, 'ways of thinking at the design and development stage of new products', From this viewpoint, the difference also be found. It seems that the most significant difference between Japan and Germany exists in the field of aeroplanes design. The German ideas in the field were very unique, therefore the authors classified and named their ideas as: A) 'Quantitative analysis' type idea, and B) 'Chemical synthetic' type idea. The former concept is composed of two ways of thinking: a) All parts essential for just flying must be used, but b) All other parts shall be rejected, as far as possible. The latter concept is that, the all additional parts necessary for the development of the above 'purified' original product should be added respectively, depending on the requests of customers. These ideas are outlined using the actual examples of German aeroplane.