이주용 교수

In OFDMA systems adopting fractional frequency reuse, we can allocate orthogonal bandwidth to femtocells, which mitigates throughput degradation of macrocell users. In this paper, we discuss the optimal power allocation for femtocells with different orthogonal subbands, based on analysis of macrocell interferences.

This paper designs a distributed Transmission Opportunity (TXOP) adaptation algorithm for IEEE802.11e Enhanced Distributed Channel Access (EDCA). Each node measures its throughput in a window and compares it with a target value. If the measured throughput is higher than the target value, the node reduces its TXOP, otherwise if the measured value is less than the target throughput, the node increases its TXOP. We show that the target throughput can be achieved in a globally stable manner.

Purpose: To analyze overall survival (OS), prostate cancer (PCa)-specific survival (PCaSS), and non-PCaSS according to the Charlson Comorbidity Index (CCI) after radical prostatectomy (RP) for PCa. Materials and Methods: Data from 336 patients who had RP for PCa between 1992 and 2005 were analyzed. Data included age, preoperativeprostate-specific antigen (PSA), prostate volume, clinical stage, and pathologicstage. Pre-existing comorbidities were evaluated by the CCI, and patients were classified

In this paper, we propose a new connection admission control (CAC) algorithm accommodating various classes of traffic, which can easily be implemented in mobile WiMAX system. The proposed CAC algorithm has three characteristics: first, the variation of air capacity is taken into account by measuring the distribution of modulation and coding scheme (MCS) levels offline; second, we estimate the mean and variance of frame occupancy ratio of each QoS flow based on declared traffic descriptors; and t

Bandwidth optimization is considered when several classes of Internet traffic are served in generalized processor sharing (GPS) servers. Internet traffic shows self-similar patterns that make it difficult to obtain analytical performance in GPS. Thus, for performance estimation of different classes of traffic, we use fluid simulation techniques that can reduce the simulation complexity, compared to packet-level simulation. Using the relationship between the guaranteed bandwidth vector and the co

Purpose: To perform real-time quantitative measurements of penile rigidity for patients with erectile dysfunction (ED) using shear-wave elastography (SWE). Materials and Methods: A total of 92 patients with clinically diagnosed ED filled out an abridged five-item version of the International Index of Erectile Function (IIEF-5) questionnaire and underwent SWE as well as penile color Doppler ultrasound (CDUS) after intracavernosal injection for penile erection. Elasticity measurements were repeate

M-LWWF/M-LWDF scheduling schemes have attracted much interest due to their ability to both stabilize queues whenever possible and control delay through parameter selection. However, a good implementation of these schedulers would require a mechanism to minimize the required fraction of the bandwidth while satisfying its stability and delay requirements. To the best of our knowledge, previous works on these scheduling policies did not address the problem of minimizing the bandwidth utilization wh

The radon gas from nature mainly considers a cause of radon problems, and it is closely affect human life cycle. Korean yellow residual soil, Hwangtoh, widely used as a building material, is considered to be one of major sources of indoor radon. However, there have, as yet, been no studies about radon from Hwangtoh in mass market brands. Here, we investigated the indoor radon concentrations and exhalation rates in four Hwangtohs from different brand names and regional features. The Closed Chambe

Radon radiation exposures in home have been posed as a potential cancer hazard. This research aims to present the basic data of the indoor radon concentration level by examining the radon exhalation rates of wood species. Radon exhalation rates from five commonly used wood species in Korean wood building construction were measured with Continuous Radon Monitor (CRM), Model 1028 (Sun Nuclear Co., USA) using the Closed Chamber Method (CCM). The mass exhalation rate was observed to vary from 0.0008

A 32-year old single man presented with azoospermia and low semen volume which was noted one and half a year ago. Transrectal ultrasonography and seminal vesiculography were performed to evaluate ejaculatory duct obstruction, and transurethral resection of the ejaculatory duct was performed using a hybrid technique of holmium:yttriumaluminium garnet laser with monopolar transurethral resection to overcome the narrow prostatic urethra. To our knowledge, this is the first report on the successful