• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.51-58
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• 2003

In this paper, we propose a group scheduling scheme to efficiently utilize network resources for core nodes in optical burst switching networks. This scheme schedules multiple bursts utilizing an interval graph to obtain the maximum stable set using the information such as arrival times and burst lengths from the collected header packets. Simultaneous scheduling of multiple bursts in a scheduling window results in lower burst loss probability and increased channel utilization than those proposed previously using one-to-one mapping. Simulation results for both cases of variable and fixed burst sizes show that the group scheduling scheme is better than the immediate scheduling, so called Latest Available Unused Channel with Void Filling, scheme in both performance metrics above mentioned.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1487-1494
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• 2011

In this paper, a novel genre classification algorithm is proposed for music recommendation system. Especially, to improve the classification accuracy, the band-pass filter for octave-based spectral contrast (OSC) feature is designed considering the psycho-acoustic model and actual frequency range of musical instruments. The GTZAN database including 10 genres was used for 10-fold cross validation experiments. The proposed multiple-octave based OSC produces better accuracy by 2.26% compared with the conventional OSC. The combined feature vector based on the proposed OSC and mel-frequency cepstral coefficient (MFCC) gives even better accuracy.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1406-1424
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• 2017

Recent advancements in network infrastructures provide increased opportunities to support data delivery over multiple paths. Compared with multi-homing scenario, overlay network is regarded as an effective way to construct multiple paths between end devices without any change on the underlying network. Exploiting multipath characteristics has been explored for TCP with multi-homing device, but the corresponding exploration with overlay network has not been studied in detail yet. Motivated by improving quality of experience (QoE) for reliable data delivery, we propose a multipath message transport protocol based on application level relay (MPMTP-AR). MPMTP-AR proposes mechanisms and algorithms to support basic operations of multipath transmission. Dynamic feedback provides a foundation to distribute reasonable load to each path. Common source decrease (CSD) takes the load weight of the path with congestion into consideration to adjust congestion window. MPMTP-AR uses two-level sending buffer to ensure independence between paths and utilizes two-level receiving buffer to improve queuing performance. Finally, the MPMTP-AR is implemented on the Linux platform and evaluated by comprehensive experiments.

• Journal of Korean Academy of Nursing
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• v.36 no.3
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• pp.571-580
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• 2006

Purpose: This study was to compare the effects among Tai-Chi exercise, aquatic Exercise, and a self-help program for knee osteoarthritis patients on symptoms of arthritis, muscle strength, balance, and difficulty of performing activities. Method: There were 50 final subjects50. A non-equivalent pretest-posttest design was used. The collected data was analyzed using SPSS for Window. One-way ANOVA and Scheffe's multiple comparison test were used 8weeks after each program. Result: There were significant differences in joint pain(p=.000), stillness (p=.001), knee extensor peak torque(p=.006), knee flexor(p=.002), and difficult of performing activity (p=.000), but there was no significant difference in balance(p=.648). The Tai-Chi group was significantly different from the self-help group for knee extensor peak torque, knee flexor and stiffness on Scheffe's multiple comparison tests. In addition, the Tai Chi group or aquatic group were significantly different from the self-help group for difficulty of performing activities(p<0.05). Conclusion: There are significant differences in the effects of the nursing intervention among the three groups. The Tai Chi group and aquatic group were significantly different from the self-help group. However, it seems that Tai-chi exercise may be more suitable than aquatic exercise in osteoarthritis exercise programs. Further studies with a longitudinal study are necessary to confirm the longer exercise period.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.16-27
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• 2012

In multi-interface multi-channel(MIMC) based tactical ad hoc networks, QoS support for required operational capacity is one of the main challenging issues for multi-hop transmissions. To support QoS in such a harsh environment, we propose a novel MAC scheme to minimize multi-hop as well as per-hop delay. The current IEEE 802.11 MAC protocols should contend to reserve the channel resource at every hop by each sender. The every-hop channel contention results in a degradation of end-to-end delay for multi-hop transmissions. The basic idea of our scheme is to make a "multi-hop reservation" at the MAC layer by using the modified RTS frame. It contains additional information such as destination information, packet priority, and hop count, etc. In addition, we differentiate the contention window area according to the packet priority and the number of hops to deliver packets in the predefined allowed latency. Our scheme can minimize the multi-hop delay and support the QoS of the critical data in real time(i.e., VoIP, sensing video data, Video conference between commanders). Our simulation study and numerical analysis show that the proposed scheme outperforms the IEEE 802.11 MAC.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.5
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• pp.345-351
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• 2015

Sounds of electrically powered vehicle components such as window lift system, roller blind, etc., are required to be more comfortable and not to irritate the people emotionally. In this paper, a study was conducted to identify the significant sound quality metric and compose the luxuriousness sound quality index of electrically powered vehicle roller blind which is part of vehicle sunroof system. Before conducting subjective evaluation, sound characteristics of roller blind was analyzed and set the target operating sound for subjective evaluation. Thus, transfer sound of roller blind which has the characteristics of sound modulation was used for subjective evaluation. Multiple linear regression analysis was carried out by chosen Zwicker's metrics which are pointed by comments of jurors. Loudness and sharpness related metrics are prime metrics in luxuriousness sound quality index we composed. Also, effect of roller blind assay when it is attached to real vehicle was identified to evaluate the validity of index.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.11
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• pp.1535-1542
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• 2001

A high resolution digital cinematic Particle Image Velocimetry(PIV) has been developed. The system consists of a high speed CCD camera, a continuous Ar-ion laser and a computer with camera controller. To improve the spatial resolution, we adopt a Recursive Technique for velocity interrogation. At first, we obtain a velocity vector fur a larger interrogation window size based on the conventional two-frame cross-correlation PIV analysis using the FFT algorithm. Based on the knowing velocity information, more spatially resolved velocity vectors are obtained in the next iteration step with smaller interrogation windows. When the correct velocity vector at the first step is found to be critical, a Multiple Correlation Validation(MCV) technique is applied to decrease the spurious vectors. The MCV technique turns out to improve SNR(Signal to Noise Ratio) of the correlation table. The developed cinematic PIV method has been applied to the measurement of the unsteady flow characteristics of a Rushton turbine mixer. A total of 3,245 instantaneous velocity vectors were successfully obtained with 4 ms time resolution. The acquired spatial resolution corresponds to the conventional high resolution digital PIV system using a 1K ${\times}$ 1K CCD camera.

• Journal of Navigation and Port Research
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• v.30 no.2
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• pp.167-172
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• 2006

In this paper, the issue of blind detection of Alamouti-type differential space-time (ST) ${\pi}/2$-shifted BPSK modulation in static Rayleigh fading channels is considered. We introduce a novel transformation to the received signal from each receiver antenna such that this binary ST modulation, which has a second-order transmit-diversity, is equivalent to QPSK modulation with second-order receive-diversity. The pre-detection combining of the result of transformation allows us to apply a low complexity detection technique specifically designed for receive-diversity, namely, scalar multiple-symbol differential detection (MSDD). With receiver complexity proportional to the observation window length, our receiver can achieve the performance 1.5dB better than that of conventional differential detection ST and 0.5dB worse than that qf a coherent maximum ratio combining receiver (with differential decoding) approximately.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.44-50
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• 2002

The fast Fourier transform (FFT) is a good method to estimate spectral density, but the frequency resolution is limited to the sampling window, and thus the precise characteristics of the spectral density for short signals are not clear. To solve the limitation, a multiple band-pass filter was introduced to estimate the precise time course of the spectral density for flash visual evoked potentials (VEPs). Signals were recorded during -200 and 600 ms using balanced noncephalic electrodes, and sampled at 1 K Hz in 12 bits. With 1 Hz and 10 ms resolutions, spectral density was estimated between 10 and 100 Hz. Background powers at the alpha-and beta-bands were high over the posterior scalp, and powers around 200ms were evoked at the same bands over the same region, corresponding to P110 and N165 of VEPs. normalized's spectral density showed evoked powers around 200 ms and suppressed powers following the evoked powers over the posterior scalp. The evoked powers above the 20Hz band were not statistically significant. However, the gamma band was significantly evoked intra-individually; details in the gamma bands were varied among the subjects. Details of spectral density were complicated even for a simple task such as watching flashes; both synchronization and desynchronization occurred with different distributions and different time courses.

• Mass Spectrometry Letters
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• v.1 no.1
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• pp.21-24
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• 2010

The development of clinical biomarkers involves discovery, verification, and validation. Recently, multiple reaction monitoring (MRM) coupled with stable isotope dilution mass spectrometry (IDMS) has shown considerable promise for the direct quantification of proteins in clinical samples. In particular, multiple biomarkers have been tracked in a single experiment using MRM-based MS approaches combined with liquid chromatography. We report here a highly reproducible, quantitative, and dynamic MRM system for validating multi-biomarker proteins using Nanoflow HPLC-Microfluidics Chip/Triple-Quadrupole MS. In this system, transitions were acquired only during the retention window of each eluting peptide. Transitions with the highest MRM-MS intensities for the five target peptides from colon cancer biomarker candidates were automatically selected using Optimizer software. Relative to the corresponding non-dynamic system, the dynamic MRM provided significantly improved coefficients of variation in experiments with large numbers of transitions. Linear responses were obtained with concentrations ranging from fmol to pmol for five target peptides.