• Journal of Wetlands Research
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• 제15권4호
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• pp.609-618
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• 2013

Curve number (CN), originally developed, compiled by 'The Natural Resources Conservation Service (NRCS)', and has been widely used throughout the world. However, there is the uncertainty of CN derived from the use of antecedent moisture condition (AMC)/Antecedent Runoff Condition (ARC). As in Korea where nearly 70% covered by mountainous area, it is still not sufficient handbook precedent to guide or support the estimation of AMC/ARC. The failure to develop formal criteria of applying AMC/ ARC will be a gaping profession and results not only in uncertainty of CN estimation in particular, but also in designing appropriate structures in Korea as a whole. This paper is aiming at presenting a critical review of AMC/ARC and deriving a procedure to deal more realistically with event rainfall-runoff over wider variety of initial conditions. Proposed methods have been developed. It is based on modifying estimated runoff to observed runoff with coefficient of determination and then applying different algebraic expression with the verification of AMC by antecedent rainfall table of NEH-1964. The result shows that algebraic expression by Arnold et al. (1996) is the most appropriate for AMC/ARC and the results of AMC/ARC estimation criteria are generally very close to each other. Therefore, this algebraic expression might be applied in South Korea condition properly.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제31권4B호
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• pp.270-277
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• 2006

In the wireless adaptive modulation and coding(AMC) systems, the modulation type of user's connection can be changed dynamically. and the ongoing connection might fail due to the change of modulation. In this paper, we approach the AMC-induced CAC problem by focusing on the guaranteed connection. Three kinds of calls, new, handoff, and modulation-changed calls, are considered. We propose a modified guard channel CAC scheme that allows the modulation-changed and handoff calls to use the guard channel. Then we analyze a Markov model for the CAC scheme with long-term AMC in mind. According to the simulation results, the proposed approach reduces the call dropping probability for modulation-changed calls, which suggests the threshold of guard channels can be determined based on the proposed approach.

• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6387-6390
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• 2014

Background: The prognostic significance of the circulating absolute monocyte count (AMC) in patients with locally advanced hepatocellular carcinoma (HCC) is uncertain. This study was designed to assess the association of circulating AMC with survival outcomes in patients diagnosed with locally advanced or metastatic HCC receiving systemic chemotherapy. Materials and Methods: Between January 1, 2005 and December 30, 2012, locally advanced or metastatic HCC patients who had Child-Pugh stage A or B disease and received systemic chemotherapy were retrospectively enrolled. Patient features including gender, age, extrahepatic metastasis, Child-Pugh stage, serum alpha-fetoprotein(AFP) level and AMC were collected to investigate their prognostic impact on overall survival(OS). Results: A total of 216 patients were eligible for the study. The optimal cut-off value of AMC for OS analysis was $0.38{\times}10^9/L$. Median OS was 5.84 months in low-AMC group (95% confidence interval [CI], 5.23 to 6.45), and 5.21 months in high-AMC group (95% CI, 4.37 to 6.04; p=0.003). In COX multivariate analysis, elevated AMC remained as an independent prognostic factor for worse OS (HR, 1.578; 95% CI, 1.120 to 2.223, p=0.009). Conclusions: Our results indiicate that circulating AMC is confirmed to be an independent prognostic factor for OS in patients with locally advanced or metastatic HCC receiving systemic chemotherapy.

• Journal of KIISE:Information Networking
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• 제31권2호
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• pp.188-195
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• 2004

We have analyzed the performance of TCP in the CDMA mobile communications systems with the adaptive modulation and coding(AMC). The wireless channel using AMC is characterized with not high error rate but highly varying bandwidth. Due to time-varying bandwidth, timeout events of TCP occurs more frequently, which leads to the throughput degradation. The analysis model is composed of the two parts. In the first part, we divide TCP packet stream into ‘packet groups’and derive the probability distribution of the wireless transmission time of each Packet group that reflects the time varying characteristics of AMC. In the second part, we formulate embedded Markov chain by making use of the results of the first part to model TCP timer mechanism and wireless transmission. Since our system model is characterized by the forward link high speed data transmission using AMC, the results reported in this paper can be used as a guideline for the design and operation of HSDPA, 1xEV-DO, and 1xEV-DV.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제32권6A호
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• pp.608-616
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• 2007

OFDM Systems for multi-user use adaptive modulation and ending (AMC) which is a method that selects suitable modulation order and code rate depending on channel state of each user. Using AMC, OFDM system can provide high quality and reliable communication. Base station using AMC scheme requires downlink channel information of each terminal to operate optimality. However, under practical system environment, it is unsuitable to transmit all channel information because uplink bandwidth of the system is limited. In this paper, we propose a flexible block-wise loading (FBL) algorithm combined with a novel CQI feedback scheme with reduced number of required bits to optimize the performance of AMC system. Proposed algorithm allocates sub-carrier groups dynamically to improve the sector throughput and outage probability performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제10권5호
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• pp.7-12
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• 2010

The bandwidth of a Jerusalem AMC was investigated based on the equivalent circuit model. Using the circuit model and the derivative of the admittance(Y'), the relation between the bandwidth and various circuit parameters was analyzed. It was shown that the substrate thickness and permeability enhance the bandwidth whereas the loadings on FSS grid degrade the bandwidth. Among the two loadings, the capacitive loading had better bandwidth characteristics than the inductive loading. AMC with single polarization was suggested to relax the bandwidth degradation by the inductive loading.

• The Journal of the Korea Contents Association
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• 제8권4호
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• pp.55-62
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• 2008

Adaptive modulation and Coding(AMC) scheme is promising technique to support the demands for high data rates and wideband proposed for 4G mobile communication system standards. In this paper, adaptive modulation and coding(AMC) based on OFDM system is analyzed through simulation for single user case and compared with SISO-OFDM and SFBC(Space frequency block coding)-OFDM. The performance analysis in terms of capacity for downlink system environments with different values of constellation size under multipath fading channel is done. The adaptive modulation and coding technique is based on perfect estimation channel. It has been observed that SFBC(Space-frequency block coding)-OFDM system gives better performance in terms of capacity.

• Journal of Korea Multimedia Society
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• 제11권9호
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• pp.1238-1244
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• 2008

Each layer operates independently in the present network structure. However, the importance of designing cross layer, which adapt between different layers, is on the rise, because of adapt to the variable communication environments. In this paper, we investigate the scheduling techniques of the cross layer. we research conventional scheduling methods and propose the multimedia service scheduling method which will be applied in future wireless communication environments. This method considers the diversity of multimedia service and manages the radio resources efficiently Moreover, we apply AMC for flexibility and improve the performance of the scheduling method. The proposed method is verified through the simulation appying variable environments.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제47권3호
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• pp.22-30
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• 2010

This paper proposes a combination system of Adaptive Modulation and Coding (AMC) and Multiple Input Multiple Output (MIMO), which improves the throughput and has a better reliability. In addition, the system includes Precoding, Antenna Subset Selection and MIMO Mode Selection scheme. Finally, we make a performance analysis of the proposed system. The principal environmental parameters for the simulation experiment consist of a frequency non-selective rayleigh fading channel and a Spreading Factor (SF) of 16. Other parameters may be included in order to fulfill the requirements of the HSDP A Standard. The proposed system has a higher throughput and more reliability than the conventional system, which does not include MIMO Mode Selection scheme, Precoding or Antenna Subset Selection. According to the simulation results, the proposed system reaches the maximum throughput at 8dB, presentlng an improvement of 6dB and twice higher throughput, respect to the conventional system. Specifically, at the point of -6dB, the conventional system reaches 2.5Mbps, while the proposed system reaches 6.4Mbps at the same SNR. Also, at the point of 2dB, each system reaches 7.5Mbps (conventional system) and 15.3Mbps (proposed system), with near twice the difference. According to the results exposed above, we can conclude that the system proposed in this paper has, as the greatest contribution, the improvement of the throughput, especially, the average throughput.

• Korean Journal of Plant Resources
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• 제27권5호
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• pp.540-545
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• 2014

The Polygonatum odoratum cv. Gungangbeaksea, bred in Gyeongsangnam-Do Agricutural Research & Extension Service, was cultured in vitro for micropropagate rapidly through the culture of rhizome explants ($5{\times}5mm$). The $7{\times}7mm$ explants of adventitious multi-bud clusters (AMC), obtained through the culture of rhizome explants (MS + 3.0 mg/L BA) were cultured on MS media with BA and TDZ. The shoot multiplication was favorable on the MS medium containing 3.0 mg/L TDZ with 2.8 in shoot number. But the formation of AMC was low in all media tested. The explants of AMC were cultured on MS media containing 1.0~5.0 mg/L TDZ and NAA to multiplicate AMC more. The formation of AMC was a little more stimulated on combined MS media of TDZ and NAA, than that with TDZ alone. The multiplication of shoots and AMC was favorable on MS media with 3.0 mg/L TDZ and 5.0 mg/L NAA, and 5.0 mg/L TDZ and 3.0 mg/L NAA. As the concentration of MS salts increased, the formation of AMC was decreased. But the formation of AMC was more stimulated, as the concentration of sucrose increased to 7%. Therefore, the multiplication of shoots and AMC was suitable on media containing 3.0~5.0 mg/L TDZ and NAA, and 7% of sucrose. The explants of AMC were rooted on media with 3.0 mg/L IBA, or 2.0 mg/L NAA with more than 80% in rooting ratio. The plantlets were treated at $5^{\circ}C$ for 8 weeks, and cultured ex vitro for 8 weeks. The survival ratio of plantlets were 100% in vermiculite, and the mixed soil with perlite 1 volumn and vermiculite 1 volumn.