• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.83-87
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• 2009

The MAC protocol of HiperLAN/2 is based on TDMA/TDD. Mobile terminal acquires a data transmission opportunity as successfulness in channel competition through RCH (Random CHannel) phase. Therefore, AP (Access Point) be able to dynamically assign optimum RCH at next frame according to the number of success and collision. In this paper, we suggest scheme that fluctuate RCH (Random CHannel) number as fixed value considering success and collision for improvement of performance in HiperLAN/2. To prove efficiency of proposed scheme, a lots of simulations are conducted and analyzed in view of throughput and access delay.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.4
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• pp.119-126
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• 1996

Influence factors and efficiency characteristics for treatment of wastewater containing phenol were studied with using Pseudomonas sp. B3. It took 130 hours to remove phenol, when only activated sludge of terminal disposal palnt of sewage was innoculated in batch culture, but it was required just 36 hours, when bacteria degrading phenol and activated sludge were simultaneously innoculated. If only phenol an carbon source was used, it necessary 36 hours for biodegradation of phenol, while glucose was added to medium, it took 73 hours. It was revealed as excellent effluent and SVI, when the F/M ratio, COD and phenol concentration were 53mg/l and 1.2mg/l, respectively, and optimum F/M ratio was revealed 0.31. The reactor were seriously shocked as reducing hydraulic retention time at constant phenol concentration more than increasing phenol concentration at constant hydraulic retention time, when volumetric loading rate was increased to $0.8kg\;phenol/m^3{\codt}d$ from $1.6kg\;phenol/m^3{\codt}d$. And also the effluent phenol concentration was 34mg/l after starting 12 hours of shocking and reactor was recovered as steady state after 65 hours of changing in the former test. Although the effluent phenol concentration was maximum value with 12mg/l after starting 20 hours of shocking and reactor was recovered as steady state after 54 hours of changing in the later test.

• Journal of Korea Port Economic Association
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• v.34 no.2
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• pp.17-30
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• 2018

The regional industry promotion system, which seeks to link the characteristics and resources of the region to its core strategic industry, is spreading the industrial resources in the form of an organic network. The Seosan-Daesan Port is the only port in the Chungcheong provinces that is equipped with international passenger dock and terminal, and it will soon have a ferry service operating to the Longyan port in Rongcheng, China in 2018. The study focuses on effects of the first international ferry operation in the provinces that are being realized with the aim of developing the regional industry. The study also analyzes the ripple effects on the tourism and port industries in the provinces by tapping into the 2013 regional inter-industry table. The analysis shows that the scheduled ferry operation will generate 47,815 million won in production and 23,423 million won in added value for the region's tourism industry. It will also generate total revenue of 12,567 million won for the port industry driven by the locally handled freight containers and the added value. Currently, the Korea-China ferry operation in other regions exhibits greater dependence on the cargo than the passengers. Thus, for the international ferry operation to and from Seosan, generating maximum employment in tourism from the passengers of the international ferry operation will require strategic marketing to attract tourists. At the same time, a steady supply of cargo needs to be sustained by maintaining a balance between import and export cargoes. Furthermore, greater efforts should be made to create more sea routes than other regions or to increase voyages for the purpose of generating more added value.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.5
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• pp.1249-1259
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• 1998

This paper proposes an efficient channel assignment method for real-time service in the IEEE 802.11 Wireless LAN system, and analyzes the supportability to real-time service and the channel utilzation of that through computer simulations. The improved MAC(Medium Access Control) protocol employing the proposed channel assignment method achieved good throughput over contention period as well as contention-free period by making real-time terminals transmit the information about their desiring value before starts of data transmissions. For performance evaluation of the proposed method, a simulation analyzing the variation of allocated bandwidths to terminals using real-time service and their buffer sizes wasexecuted. Real-time data traffics was modeled s 7-stae transition VBR sources, and asynchronous data traffics modeled as Poisson processes. In the simulation, the proposed method showed smaller variation of the bandwidth of each terminal and samller buffer size than the existing method, and also recorded good throughput over contention period.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.102-110
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• 2010

H.264 SVC(Scalable Video Coding) provides the advantages of low disk storage requirement and high scalability. However, a streaming server or a user terminal has to extract a bit stream from SVC file. This paper proposes a bit stream extraction method which can get the maximum PSNR value while date bit rate does not exceed the available network bandwidth. To do this, this paper obtains the information about extraction points which can get the maximum PSNR value offline and decides the spatial/temporal resolution of a bit stream at run-time. This resolution information along with available network bandwidth is used as the parameters to a bit stream extractor. Through experiment with JSVM reference software, we proved that proposed bit stream extraction method can get a higher PSNR value.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.9
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• pp.1414-1422
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• 2019

Objective: Two experiments were conducted to determine the effects of adaptation time and inclusion level of sugar beet pulp (SBP) on nutrient digestibility and to evaluate the ileal amino acid digestibility of SBP fed to pigs. Methods: In Exp. 1, thirty-six crossbred barrows ($85.0{\pm}2.1kg$) were allotted to 6 diets in a completely randomized design with six replicates per diet. Diets included a corn-soybean meal diet and 5 test diets containing 14.6%, 24.4%, 34.2%, 43.9%, or 53.7% SBP, respectively. The adaptation time consisted 7, 14, 21, or 28 d consecutively for each pig followed by 5 d for fecal collection. Feces were collected from d 8 to 13, d 15 to 20, d 22 to 27, and d 29 to 34, respectively. In Exp. 2, six pigs ($35.1{\pm}1.7kg$) with T-cannulas at the terminal ileum were fed to 3 diets in a replicated $3{\times}3$ Latin square design with 3 periods and 2 replicate pigs per diet. Each period consisted 5 d for diet adaptation followed by 2 d for digesta collection. Results: The digestible energy (DE) value and the apparent total tract digestibility (ATTD) of gross energy (GE), dry matter (DM), ash, and organic matter in diets linearly decreased (p<0.05) as the adaptation time increased or as the dietary SBP increased, while the ATTD of neutral detergent fibre and acid detergent fibre in diets linearly increased (p<0.01) as the dietary SBP increased. The DE value and the ATTD of GE and crude protein (CP) in SBP linearly increased (p<0.05) as the adaptation time increased, while the ATTD of CP in SBP linearly decreased (p<0.01) as the inclusion level increased. The standardized ileal digestibility of Lys, Met, Thr, and Trp in SBP was 37.03%, 51.62%, 40.68%, and 46.22%, respectively. Conclusion: The results of this study indicated that the ATTD of energy and nutrients were decreased as inclusion rate of SBP increased.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.3
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• pp.185-191
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• 1999

The fuse used in the high voltage distribution line often fails due to the active ionization caused by the strong electric field at fuse terminal. To suppress the ionization at the high voltage and high capacity current limiting fuse, the particle size and compactness of silica sand, the design, length, notch number and material of element, the diameter and length of fuse body must be considered carefully. However, these are not many proper which is treated with the inherent interrupting characteristics from many parameters at present. Because of these reasons, time and effort are needed to develop the new type fuse by the fuse designers in relation with the inherent characteristics from each of parameters. In this paper we choose 7 parameters with weight value based on study and experimentation and analyzed the characteristics of arcing period. In addition, we proposed the experimental method to experimentation and analyzed the characteristics of arcing period. In addition, we proposed the experimental method to extract the optimal design parameters with minimal effort as related the mutual effect from each of the parameters.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2002-2004
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• 1998

In this paper, the compensation algorithm of the stator resistance which is essential to improving the performance of the direct vector control system is proposed. This paper focuses on the improvement in the torque response of the direct vector control in a constant speed region. The conventional compensation algorithms are analyzed and a new method is developed to compensate the stator resistance in the direct vector control system. In addition, the effect of the variation of the stator resistance on the drive performance is analyzed for the vector control. The proposed algorithm is very simple to implement that does not require the modifications on the motor model or additional interrupts of the controller. Also, the value of the stator resistance can be obtained in real-time through the measurement of the terminal voltage and current. From the simulation and experimental results, the validity of the proposed scheme is confirmed.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1185-1195
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• 2012

In the general recording method of mobile broadcasting, all incoming broadcasting streams after recording time will be saved regardless of its content. In this case, as such that viewers do not want to record, commercial advertisement, are saved together. In order to solve these problems, the proposed method checks if the contents such as advertisements are exist in the target stream by analysing the splicing in incoming MPEG-2 TS streams and, if splicing happened, excludes incoming stream after the splicing in the recording process. In the proposed method, first the splice in the recording stream is verified using the related flags of adaptation field in the TS packet and, if judged to cause a splice, the time of splicing is to be estimated by evaluating the value of splice_countdown filed. In this way, the proposed algorithm provides the seamless recording method by estimating the time of splice and excluding the contents after the splicing. To evaluate the proposed seamless recording method, the simulation was carried out by modifying the software of the existing mobile broadcasting terminal.

• Journal of Korea Multimedia Society
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• v.9 no.1
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• pp.59-72
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• 2006

The rapid growth of technology for network and terminal devices is able to service multimedia contents in mobile environments. But as the environment of networks and the performance of devices is varied, the same quality service is very difficult to be provided for user in internet and mobile environment. Therefore, multimedia streaming system must provide an adaptive service in considering network and device environment. Video transcoding techniques are the good solution that can provide video streaming service in various network environments adaptively. This paper proposes a dynamic frame-skipping transcoding scheme to provide adaptive streaming service in various network environments. This scheme uses the prediction period for transcoding. A proposed transcoding scheme can reduce time complexity through combination of prediction period and skipping period to control frame-skipping rate in encoder. In simulation results, the performance of proposed scheme is similar to the performance of a traditional dynamic frame-skipping scheme in PSNR value. But the performance of proposed scheme outperforms the performance of traditional scheme in time complexity.