• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7B
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• pp.685-696
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• 2004

Real-time multimedia applications that require large amount of bandwidth need resource reservation before starting service for providing the QoS(i.e., Quality of Service). To reserve resources in advance, each reservation request has to notify its expectation on the required amount of resources and service duration. Using this information, a resource manager can schedule advance reservations. However, most existing resource management systems are adopting straightforward call admission control process (i.e., only immediate reservation) by checking currently available resources without considering the service duration. Hence, the resource management system that supports advance reservation has to manage confliction caused by indefinite service duration of immediate reservation. Even though the separation of resource pool according to type of reservation can prevent the confliction, it causes low resource utilization. In this paper, we propose an effective resource management scheme that supports both immediate and advance reservations by sharing resources dynamically. Using network cost function, the proposed scheme determines and adaptively adjusts resource boundary according to the confliction rate by varying weight parameters. And also, we define user utility function to quantify user satisfaction based on how well the reserved resource is guaranteed during service time. Simulation results using NS-2 network simulator show that the proposed scheme can achieve better resource utilization with preferable QoS than other schemes like static resource partitioning.

• Journal of Acupuncture Research
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• v.31 no.4
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• pp.109-119
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• 2014

Objectives : The aim of this study is to observe clinical characteristics and treatment outcomes of inpatients admitted to a Korean medicine hospital for shoulder pain based on magnetic resonance imaging(MRI) findings. Methods : 28 patients with MRI data were included. Data on MRI findings, duration of pain, and treatment effects were collected. To measure treatment outcomes, verbal numerical rating scale(VNRS), range of motion(ROM), and a clinical condition grading system were used. Results : 1. The patient population was 75.0 % female and 39.3 %(n=11) belonged to the 51~60-year-old age group. In the under 40 population, 1 or less MRI findings were found. 2. As for the type of disorder, 82.1 % of the patients were diagnosed with 'Supraspinatus lesion', 39.3 % with 'subacromial-subdeltoid(SA-SA) bursitis', and 28.6 % with 'Adhesive capsulitis' 3. Numerous correlations could be made between duration of pain and MRI findings. 'rotator cuff full thickness tear' was more prevalent in acute shoulder pain patients, and 'Adhesive capsulitis' in chronic patients. 4. VNRS and ROM at the time of discharge had significantly improved as compared to VNRS and ROM at the time of admission. 5. As for correlation between MRI findings and clinical condition grade, patients diagnosed with 'rotator cuff partial tear' reported to be in 'good' condition or better whereas those with 'rotator cuff full thickness tear' reported to be in 'fair' condition or worse. Conclusions : Patients admitted to a Korean Medicine hospital for shoulder pain had varying degrees of severity as shown on MRI. Almost all lesions responded well to Korean medicine treatment.

• Nuclear Engineering and Technology
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• v.28 no.2
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• pp.175-184
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• 1996

A nuclide transfer by utilizing mass transfer coefficient and barrier response function defined for each barrier is proposed, by which the final nuclide transfer rate into the sea water can be evaluated. When simple and immediate quantification of the nuclide release is necessary in the conservative aspect, using this kind of approach may be advantageous since each layered barrier can be treated separately from other media in series in the repository system, making it possible to apply separate solutions in succession to other various media. Although one disadvantage is that while flux continuity can be maintained at the interface by using the exit nuclide flux from the first medium as the source flux for the next one, there may be no guarantee for concentration continuity, this problem could be eliminated assuming that there is no boundary resistance to mass transfer across the interface. Mass transfer coefficient can be determined by the assumption that the nuclide concentration gradient at the interface between adjacent barriers remains constant and barrier response function is obtained from an analytical expression for nuclide flow rate out of each barrier in response to a unit impulse into the barrier multiplied by mass transfer coefficient. Total time-dependent nuclide transfer rate from the barrier can then be obtained by convoluting the response function for the barrier with a previously calculated set of time-varying input of nuclide flow rate for the previous barrier.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.137-144
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• 2004

ECG signals are often contaminated with high-frequency noise such as muscle artifact, power line interference, and others. In the ECG signal processing, especially during a pre-processing stage, numerous noise removal techniques have been used to reduce these high-frequency noise without much distorting the original signal. This paper proposes a new type of digital filter with a continuously variable cutoff frequency to improve the signal quality This filter consists of a cutoff frequency controller (CFC) and variable cutoff frequency lowpass filter (VCF-LPF). From the noisy input ECG signal, CFC produces a cutoff frequency control signal using the signal slew rate. We implemented VCF-LPF based on two new filter design methods called convex combination filter (CCF) and weight interpolation fille. (WIF). These two methods allow us to change the cutoff frequency of a lowpass filter In an arbitrary fine step. VCF-LPF shows an excellent noise reduction capability for the entire time segment of ECG excluding the rising and falling edge of a very sharp QRS complex. We found VCF-LPF very useful and practical for better signal visualization and probably for better ECG interpretation. We expect this new digital filter will find its applications especially in a home health management system where the measured ECG signals are easily contaminated with high-frequency noises .

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.357-363
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• 2015

The development of the environment-friendly tire that meets the standard requirements according to tire labeling system can be improved through using highly homogeneous silica immobilized zinc oxide nanoparticles. In this study, a considerable amount of nanoporous silica was essentially added into nano zinc oxide to improve the physiochemical properties of the formed composite. The introduction of nanoporous silica materials in the composite facilitates the improvement of the wear-resistance and increases the elasticity of the tread. Therefore, the introduction of nanoporous silica can replace carbon black as filler in the formation of composites with desirable properties for conventional green tire. Herein, mesoporous silica immobilized zinc oxide nanoparticle with desirable properties for rubber compounds was investigated. Composites with homogeneous dispersion were obtained in the absence of dispersants. The dispersion stability was controlled through varying the molar ratio, ageing time and mixing order of the reactants. A superior dispersion was achieved in the sample obtained using 0.03 mol of zinc precursor as it had the smallest grain size (50.5 nm) and then immobilized in silica aged for 10 days. Moreover, the specific surface area of this sample was the highest ($649m^2/g$).

• Journal of the Korea Society of Computer and Information
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• v.18 no.10
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• pp.1-12
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• 2013

This paper explores design space of many-core processors for a fire feature extraction algorithm. This paper evaluates the impact of varying the number of cores and memory sizes for the many-core processor and identifies an optimal many-core processor in terms of performance, energy efficiency, and area efficiency. In this study, we utilized 90 samples with dimensions of $256{\times}256$ (60 samples containing fire and 30 samples containing non-fire) for experiments. Experimental results using six different many-core architectures (PEs=16, 64, 256, 1,024, 4,096, and 16,384) and the feature extraction algorithm of fire indicate that the highest area efficiency and energy efficiency are achieved at PEs=1,024 and 4,096, respectively, for all fire/non-fire containing movies. In addition, all the six many-core processors satisfy the real-time requirement of 30 frames-per-second (30 fps) for the algorithm.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.18 no.1
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• pp.42-63
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• 1992

In order to investigate the effect of nonionic surfactants on the antimicrobial activity of preservatives in the presence and absence of p.0.E(20) Sorbitan fatty acid ester commonly used in cosmetics and pharmaceutical systems, these experiments were carried out by determining Minimum Inhibitory Concentration(MIC) values and MIC values of adaptation against test organisms. And also the inactivation of the preservative against each microorganism in formula added with various concentrations of P.0.E(20) Sorbitan monostearate were measured by use of a preservative death time curve The results obtained were as fort low : 1) Nonionic surfactant inactivated Methylparaben to varying extents, but not Imidazolidinyl urea. 2) A combined preservative system was inactivated to a little extent (range of 0.16-0.20% Conc.), no adaptation was observed for the 5. aureus ATCC 6538. Imidazolidinyl urea complex combined with Methylparaben had a broad antibacterial spectrum against the Gram(.) and the Gram(-) bacteria It was found that preservatives had a synergistic effect by use of mixed form of preservatives, 3) In formula preserved with 0.2% Methylparaben containing 0.5, 1.0 and 2.0% P.0.E(20) Sorbitan monostearate, E. coli ATCC 10s36 and P. aeruginosa NCTC 10490 died quickly within in 2hr 4) However, from Fig.5, S. aereus ATCC 6538 died more slowly within increasing surfactant concentration and the D-values(Decimal reduction time) were 5.2, 8 and 14 hr. for samples containing 0.5, 1 0 and 2.0% P 0. E(20) Sorbitan monostearate, respectively. 5) In the case of Methylparaben, no adaptation for the E. coli ATCC 10536 6) All of the nonionic surfactant, p.0. E(20) Sorbitan fatty acid ester used in the experiments decreased the effectiveness of Methylparaben, but not of Imidazolidinyl urea.

• The Journal of the Acoustical Society of Korea
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• v.34 no.1
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• pp.20-35
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• 2015

Underwater acoustic channel impulse responses (CIR) are influenced by sound speed profile (SSP), and the variation of CIR has significant effects on the performance of underwater acoustic communication systems. A significant change of SSP can occur within a short period, which must be considered during the design of underwater acoustic modems. This paper statistically analyzes the effect of the variation of SSP on the long-range acoustic signal propagation in shallow-water with thermocline using numerical modeling based on the data acquired from JACE13 experiment near Jeju island. The analysis result shows that CIR changes variously according to the SSP and the depth of the transmitter and receiver. We also found that when the transmitter and receiver are deeper, the variation of sound wave propagation pattern is smaller and signal level becomes higher. All CIR obtained in this study show that a series of bottom reflections due to downward refraction and small bottom loss in the shallow water with thermocline can be very important factor for long-range signal transmission and the performance of underwater acoustic communication system in time varying ocean environment can be very sensitive to the variation of SSP even for a short period of time.

• Journal of Korea Water Resources Association
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• v.56 no.7
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• pp.439-449
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• 2023

Recent advancements in data measuring technology have facilitated the installation of various sensors, such as pressure meters and flow meters, to effectively assess the real-time conditions of water distribution systems (WDSs). However, as cities expand extensively, the factors that impact the reliability of measurements have become increasingly diverse. In particular, demand data, one of the most significant hydraulic variable in WDS, is challenging to be measured directly and is prone to missing values, making the development of accurate data generation models more important. Therefore, this paper proposes an adversarially trained autoencoder (ATAE) model based on generative deep learning techniques to accurately estimate demand data in WDSs. The proposed model utilizes two neural networks: a generative network and a discriminative network. The generative network generates demand data using the information provided from the measured pressure data, while the discriminative network evaluates the generated demand outputs and provides feedback to the generator to learn the distinctive features of the data. To validate its performance, the ATAE model is applied to a real distribution system in Austin, Texas, USA. The study analyzes the impact of data uncertainty by calculating the accuracy of ATAE's prediction results for varying levels of uncertainty in the demand and the pressure time series data. Additionally, the model's performance is evaluated by comparing the results for different data collection periods (low, average, and high demand hours) to assess its ability to generate demand data based on water consumption levels.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.232-237
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• 2008

A method to generate electric power from small scale water tank. For this purpose, manufacturing tank is investigated, measuring water level change at any time, and finally comparing experimental and theoretical value, are performed. Inner and outer tank are made to simulate flood and ebb generation. Two sets of pipe are connected between tanks, and experiments are performed under varying flowrate. Coefficients of flowrate are calculated comparing water level change data and theoretical value. Measured and theoretical water levels are highly correlated, and this ascertains that analytical equation simulates real water level changes well. Flowrate change depending on the existence of propeller and valve, on flood and ebb generation, shows the necessity of experiments in the process of manufacturing electric power system. Moreover, total energy calculated from experimental data agrees well with that of theoretical equation. In spite of small tidal power output, this generating system with optimum water tank can be applied to any place where high water level change occurs, and can make a contribution to producing new and renewable energy consequently.