• Journal of Korea Multimedia Society
• /
• v.10 no.7
• /
• pp.893-901
• /
• 2007

Since real-time multimedia applications requiring duality-of-service guarantees are spreading over mobile and wireless networks, energy efficiency in wireless channels is becoming more important. Energy consumption in the channels can be reduced with decreasing the rate of scheduler's outgoing link by means of Dynamic Modulation Scaling (DMS). This paper proposes a fair queuing algorithm, termed Rate Efficient Fair Queuing (REFQ), in order to reduce the outgoing link's rate, which is based on the Latency-Optimized Fair Queuing algorithm developed to enhance Weighted Fair Queuing (WFQ). The performance evaluation result shows that REFQ does decrease the link rate by up to 35% in comparison with that in WFQ, which results in reducing the energy consumption by up to 90% when applied to the DMS based radio modem.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.4C
• /
• pp.343-355
• /
• 2003

Fair bandwidth allocations at routers protect adaptive flows from non-adaptive ones and may simplify end-to end congestion control. However, traditional fair bandwidth allocation mechanisms, like Weighted Fair Queueing and Flow Random Early Drop, maintain state, manage buffera and perform packet scheduling on a per-flow basis. These mechanisms are more complex and less scalable than simple FIFO queueing when they are used in the interi or of a high-speed network. Recently, to overcome the implementation complexity problem and address the scalability and robustness, several fair bandwidth allocation mechanisms without per-flow state in the interior routers are proposed. Core-Stateless Fair Queueing and Rainbow Fair Queuing are approximates fair queueing in the core-stateless networks. In this paper, we proposed simple Layered Fair Queueing (SLFQ), another core-stateless mechanism to approximate fair bandwidth allocation without per-flow state. SLFQ use simple layered scheme for packet labeling and has simpler packet dropping algorithm than other core-stateless fair bandwidth allocation mechanisms. We presente simulations and evaluated the performance of SLFQ in comparison to other schemes. We also discussed other are as to which SLFQ is applicable.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.6 no.11
• /
• pp.2956-2979
• /
• 2012

Along with the development of Information Technology, online transactions through Internet have become more popular for the reasons of convenience and efficiency. In order to provide secure and reliable online transactions, an effective electronic payment protocol is crucial. In this paper, we propose a novel electronic payment protocol for digital product transactions with an offline arbiter to achieve fair exchange, automated dispute resolution, customer anonymity, and customer unlinkability. In our protocol a product token is adopted to eliminate the need of key management for digital product decryption in the offline arbiter. In addition, Elliptic Curve Cryptography (ECC)-based self-certified public key is utilized to further reduce computing overheads. According to our analysis, the efficiency of our protocol can be greatly increased in comparison with previous literatures.

• ETRI Journal
• /
• v.16 no.3
• /
• pp.27-41
• /
• 1994

This paper provides a performance study of multistage interconnection networks in packet switching environment. In comparison to earlier work, the model is more extensive - it includes several parameters such as multiple-packet messages, variable buffer size, and wait delay at a source. The model is also uniformly applied to several representative networks and thus provides a basis for fair comparison as well as selection of optimal values for parameters. The complexity of the model required use of simulation. However, a partial analytical model is provided to measure the congestion in a network.

• Journal of Communications and Networks
• /
• v.12 no.1
• /
• pp.30-42
• /
• 2010

In this work we consider the problem of downlink resource allocation for proportional fairness of long term received rates of data users and quality of service for real time sessions in an OFDMA-based wireless system. The base station allocates available power and subchannels to individual users based on long term average received rates, quality of service (QoS) based rate constraints and channel conditions. We formulate and solve a joint bandwidth and power optimization problem, solving which provides a performance improvement with respect to existing resource allocation algorithms. We propose schemes for flat as well as frequency selective fading cases. Numerical evaluation results show that the proposed method provides better QoS to voice and video sessions while providing more and fair rates to data users in comparison with existing schemes.

• Journal of the Korean housing association
• /
• v.26 no.5
• /
• pp.19-26
• /
• 2015

This study examined whether the Fair Housing Amendments Act of 1988 (FHAA) in the US provides more home accessibility features and reduces the home accessibility problems of senior residents with physical disability. The 2011 American Housing Survey data with a sample of 2,326 senior residents age 55 and over with physical disability and living in multifamily housing built between 1970 and 2011 were analyzed. We compared senior residents living in multifamily before (1970-1990) and after (1991-2011) the FHAA. The results show that senior residents living in multifamily housing before the FHAA were at a greater disadvantage because they were more likely to live in older buildings located in urban areas, yet paid lower rent and received government subsidies. This study confirmed that the FHAA enabled residents of multifamily housing to have more home accessibility features. However, there was no significant difference in perceived home accessibility problems between the two groups, indicating that senior residents in multifamily housing have experienced home accessibility problems both before and after the FHAA. This study has important implications for housing policy makers to consider home accessibility features for multifamily housing buildings before the FHAA, and to revisit if the FHAA sufficiently compensates physical disability of senior resident living in multifamily housing after the FHAA.

• Clinics in Shoulder and Elbow
• /
• v.2 no.2
• /
• pp.120-125
• /
• 1999

Objectives : To evaluate the effects of arthroscopic acromioplasty and debridement for partial thickness articular side rotator cuff tears, Method: We divided 97 patients into 2 groups according to treatment protocol, with both groups having confirmed intra-articular partial tears of the rotator cuff. In group Ⅰ, we debrided the frayed and fibrotic cuff margin while in group II, we performed subacromial decompression in addition to debridement. After the surgery we checked all the patients with the modified UCLA shoulder rating scale. Results: The follow-up observation 12 months after surgery revealed that 44 patients in group I were rated as excellent in 32 cases, good in 10 cases, fair in 1 case, and poor in one case, while 53 patients in group II, were rated as excellent in 38 cases, good in 17 cases, and fair in 2 cases. Twenty-four month after surgery we observed that patients in group I were rated as excellent in 23 cases, good in 16 cases, fair in 4 cases, and poor in 1 case, while patients in group II were rated as excellent in 34 cases, good in 17 cases, and fair in 6 cases. Conclusion: The use of acromioplasty on partial thickness tears of rotator cuff, even in the cases of intra-articular nature, is preferable to the procedure performed without it.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.822-827
• /
• 2005

Recently engineering systems problems become quite large and complicated. For those problems, design requirements are fairly complex. It is not easy to design such systems by considering only one discipline. Therefore, we need a design methodology that can consider various disciplines. Multidisciplinary Design Optimization (MDO) is an emerging optimization method to include multiple disciplines. So far, about seven MDO methodologies have been proposed for MDO. They are Multidisciplinary Feasible (MDF), Individual Feasible (IDF), All-at-Once (AAO), Concurrent Subspace Optimization (CSSO), Collaborative Optimization (CO), Bi-Level Integrated System Synthesis (BLISS) and Multidisciplinary Optimization Based on Independent Subspaces (MDOIS). In this research, the performances of the methods are evaluated and compared. Practical engineering problems may not be appropriate for fairness. Therefore, mathematical problems are developed for the comparison. Conditions for fair comparison are defined and the mathematical problems are defined based on the conditions. All the methods are coded and the performances of the methods are compared qualitatively as well as quantitatively.

• 한국전산유체공학회:학술대회논문집
• /
• 1995.04a
• /
• pp.44-68
• /
• 1995

In the present paper, visualization techniques in fluid dynamic experiments such as Schlieren photograph are numerically simulated so that the same output as the experimental flow visualization can be obtained from the computed results for the fair comparison. Numerical methods to simulate optical visualizations, that are Schlieren photograph, shadowgraph and interferogram, are considered. Some examples of pictures obtained by the present methods show the importance of the simulations of visualization techniques for the correct comparisons of the computations and experiments.

• Journal of Korean Physical Therapy Science
• /
• v.8 no.1
• /
• pp.893-906
• /
• 2001

The purposes of this study were to compare pelvic tilt. range of motion(ROM) of hip rotation, and leg length difference before and after manipulation and to investigate correlation between changes of each variables after manipulation of sacroiliac pint in 31 low back pain patients(11 males, 20 females) with sacroiliac pint dysfunction. The sacroiliac pint of patients was manipulated on the side of anterior pelvic tilt, using the technique described by Stoddard(1962) and Greenmann (1996). I used this technique because it usually eliminated sacroiliac Pint dysfunction in one treatment session. SPSS for window computer system was used to analyze the data. Also t-test was performed for comparison of the variables before and after manipulation, and Pearson product-moment correlation analysis and regression analysis were performed for changes of each variables after manipulation. The result were as follows: 1. The pelvic tilt after manipulation was significantly decreased(mean=$2.79^{\circ}$) compared with the pelvic tilt before manipulation(p=.001). 2. The PROM of hip internal rotation ipsilateral to anterior pelvic tilt after manipulation significantly decreased (mean = $1.88^{\circ}$) compared with hip internal rotation before manipulation (p=.008). The PROM of hip internal rotation ipsilateral to posterior pelvic tilt after manipulation significantly increased(mean = $1.29^{\circ}$) compared with hip internal rotation before manipulation (p=.029). 3. The PROM of hip external rotation ipsilateral to anterior pelvic tilt after manipulation significantly increased(mean=$2.42^{\circ}$) compared with the hip external rotation before manipulation(p=$2.42^{\circ}$) compared with the hip external rotation ipsilateral to posterior pelvic tilt after manipulation significantly decreased(mean = $1.84^{\circ}$) compared with the hip external rotation before manipulation (p=.008). 4. Leg length difference after manipulation significantly decreased(mean=2.15 mm) compared with leg length difference before manipulation (p=.008). Regression analysis revealed that a fair correlation was found between change in leg length difference and change in anterior pelvic tilt after manipulation(p=.009). 5. Pearson product-moment correlation coefficient was used to assess differences of the variables after manipulation. A fair correlation was found between change in leg length difference and change in anterior pelvic tilt after manipulation(r=.462, p<.01). A fair correlation was found between change in anterior pelvic tilt and change in hip internal rotation ipsilateral to anterior pelvic tilt(r=.397, p<.05) and between change in anterior pelvic tilt and change in hip external rotation ipsilateral to anterior pelvic tilt(r=.516, p<.01). A fair correlation was found between change in posterior pelvic tilt and changes in hip internal rotation ipsilateral to posterior pelvic tilt (r=.441, p<.05) and between change in posterior pelvic tilt and change in hip external rotation ipsilateral to posterior pelvic tilt(r=.361, p<.05). A fair correlation was found between change in hip internal rotation ipsilateral to anterior pelvic tilt and change in hip external rotation ipsilateral to posterior pelvic tilt(r=.388, p<.05) and between change in hip internal rotation ipsilateral to posterior pelvic tilt and change in hip internal rotation ipsilateral to anterior pelvic tilt(r=.426. p<.05).