• Journal of KIISE:Information Networking
• /
• v.29 no.4
• /
• pp.358-367
• /
• 2002

The IETF Differentiated Services (Diffserv) WG focused on Providing service differentiation on the Internet. One problem of the Diffserv Assured Services (AS) architecture is that it cannot guarantee fairness and throughput assurance. In this paper, we propose two schemes for guaranteeing fairness among the various target rates in the AS architecture. One is a variant of RED with IN and OUT (RIO), called the improved RIO (IRIO). The other is a variant of Time Sliding Window (TSW), called the improved TSW (ITSW). To validate the Proposed schemes, their behaviors are then examined under various simulation environments. The simulation results showed that IRIO and ITSW improved fairness and the throughput assurance in the AS architecture.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.3
• /
• pp.18-26
• /
• 2007

One basic function of glazing system has always been the maintenance of visual contact with the natural environment-a fundamentally ecological function. In addition, penetration light through glazing system have an effect on variable atmosphere of interior. In this study, a typical office space was selected as a evaluation model and a 1/10 scale model was made. The conventional window, differentiated window and interior lightshelf were designed to enhance daylighting performance. The chromaticity and color temperature of interior space was measured using Prometric 1421. The result showed that transmittance by wavelength range of the glazing had an effect on chromaticity and color temperature. Also, color temperature of indoor environment were increased by $5{\sim}20[%]$ using differentiated window and interior lightshelf. Accordingly, it is thought that the use of a daylighting system will create activate indoor atmosphere.

• Fashion & Textile Research Journal
• /
• v.17 no.4
• /
• pp.501-512
• /
• 2015

This study was to consider and analyze of fashion window display design at Printemps department store in Paris, France which has tried continuously space presentations through the sensibility and differentiated strategy. The framework for analysis of this study was established by related precedent studies. Data collection was done by searching related specialty publications and website of Printemps department store, and the results of this study were drawn through qualitative analysis of experts' group. The results are as follows. Printemps department store set up presentation types of fashion window display design's themes that have been developed by the method of display presentation such as symbolic, ambience, surrealistic, realistic, and information. The most frequently used presentation development techniques applied in windows' VP of Printemps were the 'transferal of daily space', 'transferal of unexpected space', 'exaggeration of animal & plant', and 'descriptive narrative scene.' In addition, the display theme components such as the materials that can be easily accessible in everyday life, unique directing props, the memory or childhood, the image of animal or plant, and lighting etc. We found that the major colors of window display design at Printemps department store were purple, blue and black during the period from 2009 to 2014.

• The Research Journal of the Costume Culture
• /
• v.21 no.1
• /
• pp.17-30
• /
• 2013

The purpose of this study is to consider and analyze the VM's characteristics of Maison Herm$\grave{e}$s which has tried continuously space presentations through the sensibility and differentiated strategy focusing on the flagship store window displays of Herm$\grave{e}$s. The framework for analysis of this study is established by related precedent studies. The results of this study were drawn through qualitative analysis of experts' group. The results of this study are as follows. Maison Herm$\grave{e}$s window displays have been unfolded a total of 57 times for 10 years, and have introduced a variety of themes by cooperating with 40 artists in various fields. Herm$\grave{e}$s set up eight types of themes in order to show the window displays, and these themes have been developed by the method of display presentation such as surrealistic, symbolic, mood, realistic, information. A majority of the participating artists was the Japanese. In addition, the display components such as the materials that can be easily accessible in everyday life, the object productions that were embodied the tangible and intangible image, the nostalgia, the child's world, good, colors, etc., were most frequently utilized for an effective display presentation of the themes that have been set according to each season. The most frequently used development techniques applied Herm$\grave{e}$s windows' VP were the 'd$\acute{e}$paysement', 'the descriptive narrative', and 'scene of dramatic contrast'. It turned out that a majority of the primary colors to make up Herm$\grave{e}$s window displays were analyzed by the red-orange and white color.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37 no.3C
• /
• pp.224-232
• /
• 2012

Priority MAC is an important issue in every communication system when we consider differentiated service applications. In this paper, we propose a mechanism to support priority MAC based on multi-parameters for IEEE 802.15.7 visible light communication (VLC). By using three parameters such as number of backoff times (NB), backoff exponent (BE) and contention window (CW), we provide priority for multi-level differentiated service applications. We consider beacon-enabled VLC personal area network (VPAN) mode with slotted version for random access algorithm in this paper. Based on a discrete-time Markov chain, we analyze the performance of proposed mechanism under non-saturation environments. By building a Markov chain model for multi-parameters, this paper presents the throughput and transmission delay time for VLC system. Numerical results show that we can apply three parameters to control the priority for VLC MAC protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.7
• /
• pp.3446-3464
• /
• 2017

Backoff mechanism serves as one of the key technologies in the MAC-layer of wireless mobile networks. The traditional Binary Exponential Backoff (BEB) mechanism in IEEE 802.11 Distributed Coordination Function (DCF) and other existing backoff mechanisms poses several performance issues. For instance, the Contention Window (CW) oscillations occur frequently; a low delay QoS guarantee cannot be provided for real-time transmission, and services with different priorities are not differentiated. For these problems, we present a novel Multi-Priority service differentiated and Adaptive Backoff (MPAB) algorithm over IEEE 802.11 DCF for wireless mobile networks in this paper. In this algorithm, the backoff stage is chosen adaptively according to the channel status and traffic priority, and the forwarding and receding transition probability between the adjacent backoff stages for different priority traffic can be controlled and adjusted for demands at any time. We further employ the 2-dimensional Markov chain model to analyze the algorithm, and derive the analytical expressions of the saturation throughput and average medium access delay. Both the accuracy of the expressions and the algorithm performance are verified through simulations. The results show that the performance of the MPAB algorithm can offer a higher throughput and lower delay than the BEB algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38B no.10
• /
• pp.817-823
• /
• 2013

This paper examined the performance of differentiated services applied to each different traffic. For this purpose, we used three traffics which have a different quality of service and generate packets from a specific source to destination. To allocate a proper code point according to QoS, a common policy which is the simple policy model of time sliding window with 3 color marking (TSW3CM) was established to each traffic. To evaluate the performance, we investigate and compare code points to each traffic. Simulation results using NS-2 showed that the code points 10, 11, and 12 can be differently allocated to each traffic according to its sending rates 1Mbps, 2.5Mbps, and 4Mbps.

• Journal of Distribution Research
• /
• v.2 no.1
• /
• pp.35-57
• /
• 1997

In retailing, it seems very important to examine how consumers perceive in store design factors such as instore space for walking, product arrangement styles, instore display types, window sizes, and possibly others. Furthermore, consumers perceptions of various designs would be differentiated by consumers shopping patterns such as actual shopping versus window shopping. This article empirically investigates how various desings create different consumer reactions measured by consumer mood and store image depending on the types of consumer shopping. It was found that design factors such as open, focused, and big would create better consumer mood and consumer perceptions of store image than closed, unfocused, and small. Another finding was that consumer perceptions would interact with consumer shopping patterns. Based on the research findings, some implications are discussed in the article.

• Journal of KIISE:Computing Practices and Letters
• /
• v.14 no.2
• /
• pp.191-195
• /
• 2008

This paper proposes a technique for improving IEEE 802.11e EDCA's performance by dynamically adjusting each class's contention window size based on each class's traffic amount. For providing differentiated service differently from 802.11, 802.11e EDCA maintains four classes each of which specifies different static minimum and maximum contention window sizes. Since the initial window sites significantly affect the 802.11e performance, several window adjustment schemes have been proposed. One of the schemes known as CWminAS (CWmin Adaptation Scheme) dynamically and synchronously determines the four windows' site based on the periodically measured collision rate. This method, however, can lower the send probability of high priority classes since it can't differentiate their collisions from those of low priority classes, leading to the channel underutilization. For solving this problem, we propose ACATICT(Adaptive Contention-window Adjustment Technique based on Individual Class Traffic) algorithm which adapts each class window size based on each individual collision rate rather than one average collision rate. Our simulation experiments show that ACATICT achieves better utilization by around 10% at maximum.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• v.44 no.3
• /
• pp.80-87
• /
• 2007

In this paper, we investigate an enhancement method for Western epigraphic images, which is based on local statistics. Image data is partitioned into two regions, background and information. Statistical and functional analyses are proceeded for image modeling. The Western epigraphic images, for the most part, have shown the Gaussian distribution. It is clarified that each region can be differentiated statistically. The local normalization process algorithm is designed on this model. The parameter is extracted and it‘s properties are verified with the size of moving window. The spatial gray-level distribution is modified and regions are differentiated by adjusting parameter and the size of moving window. Local statistics are utilized for realization of the enhancement, so that difference between regions can be enhanced and noise or speckles of region can be smoothed. Experimental results are presented to show the superiority of the proposed algorithm over the conventional methods.