• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1313-1336
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• 2020

Cognitive radio (CR) is regarded as an effective approach to avoid the inefficient use of spectrum. However, CRNs have more special security problems compared with the traditional wireless communication systems due to its open and dynamic characteristics. Primary user emulation attack (PUEA) is a common method which can hinder secondary users (SUs) from accessing the spectrum by transmitting signals who has the similar characteristics of the primary users' (PUs) signals, and then the SUs' quality of service (QoS) cannot be guaranteed. To handle this issue, we first design a multiple-phase energy detection scheme based on the cooperation of multiple SUs to detect the PUEA more precisely. Second, a joint SUs scheduling and power allocation scheme is proposed to maximize the weighted effective capacity of multiple SUs with a constraint of the average interference to the PU. The simulation results show that the proposed method can effectively improve the effective capacity of the secondary users compared with the traditional overlay scheme which cannot be aware of the existence of PUEA. Also the good delay QoS guarantee for the secondary users is provided.

• 한국축산식품학회지
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• 제23권3호
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• pp.215-220
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• 2003

육제품에 발색제로 사용되고 있는 아질산염의 사용을 가능한 줄이고자 레드비트 색소와 동물성 식이 섬유인 키토산을 첨가하여 소시지를 조제하여 발색효과, 아질산염 잔존량, 보수력, 경도 및 pH의 변화에 대하여 검토하였다. 실험 결과는 레드비트 색소의 혼용은 소시지의 색을 좋게 할 뿐만 아니라 아질산염 소거작용의 효과, 보수력 및 연도의 증진에도 효과적이었으며, chitosan의 첨가는 아질산염의 소거작용을 제외한 소시지의 색, 보수력, 연토에 효과적이었다. 한편 D-cyclodextrine의 첨가는 보수력, 연도에 효과적이었으며, pyrophosphate의 첨가는 보수력에서만 효과를 나타내었다. 따라서 소시지 제조시에 아질산염이 발색의 목적으로 사용되는 한 레드비트의 색소 및 chitosan을 이용하는 것은 아질산염의 현재의 사용량을 1/2 정도로 줄일 수 있다고 사료되었으며, 특히 레드비트색소는 아질산염의 소거작용의 효과도 나타내었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2001년도 학술발표회 발표논문집
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• pp.324-329
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• 2001

Sediment yields from the reservoir watershed areas and raising of the spillway crest for the agricultural reservoir capacity enlargement were investigated and analysed through the 21 pilot reservoirs, have irrigated areas 200has. and over in the Kyoungpook province. In these studies, (1), the correlation analysis between various watershed characteristics and annual specific sediment yields were derived and (2), the excess effective reservoir capacity of the over 0.5m above the spillway crest could be estimated. In brief, catchment area should strongly be correlated with the annual specific sediment yields (R=0.90), the other side, average slope of the main stream is less than catchment area. The excess effective capacity of reservoir enlargement by the raising of spillway crest at 0.5m-height was resulted 12.1% of increasing capacity compare with the original reservoir capacity.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2010년도 춘계 학술논문 발표대회 1부
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• pp.25-27
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• 2010

Helical steel piles are being widely used in foundation for the buildings in urban areas because of their high compressive and tensile capacities. Helical steel piles have many advantages; ease installation, a vibration-free and low level of noise process, and so on. However, the most researches are about the capacity of helical steel piles under uplift condition. Therefore, this paper focuses on the capacity under compressive loading according to the soil condition. The bearing capacity of helical steel piles varies with the diameter of the helix and shaft and the bearing area of helical steel piles is not always identical with the sum of helix and shaft area due to the difference of each bearing mechanism. Therefore, the experiment with the parameters of the ratio of helix and shaft diameter and soil condition will be carried out to survey the effective helix area under a given soil condition for the bearing capacity of helical steel piles.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.704-715
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• 2016

In this paper, we explore a low-complex bandwidth allocation (BA) scheme with multi-level service guarantees in VLC-OFDM systems. Effective capacity theory, which evaluates wireless channel capacity from a novel view, is utilized to model the system capacity under delay QoS constraints of the link layer. Since intensity modulation of light is used in the system, problems caused by frequency selectivity can be neglected. Then, the BA problem can be formulated as an integer programming problem and it is further relaxed and transformed into a concave one. Lagrangian formulation is used to reformulate the concave problem. Considering the inefficiency of traditional gradient-based schemes and the demand for distributed implementation in local area networks, we localize the global parameters and propose a quasi-distributed quadratic allocation algorithm to provide two-level service guarantees, the first level is QoS oriented, and the second level is QoE oriented. Simulations have shown the efficient performance of the proposed algorithm. The users with more stringent QoS requirements require more subcarriers to guarantee their statistical delay QoS requirements. We also analyze the effect of subcarrier granularity on the aggregate effective capacity via simulations.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.644-654
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• 2024

After the Tohoku earthquake and tsunami (Japan, 2011), regulatory efforts to mitigate external hazards have increased both the safety requirements and the total capital cost of nuclear power plants (NPPs). In these circumstances, identifying not only disaster robustness but also cost-effective capacity setting of NPPs has become one of the most important tasks for the nuclear power industry. A few studies have been performed to relocate the seismic capacity of NPPs, yet the effects of multiple hazards have not been accounted for in NPP capacity optimization. The major challenges in extending this problem to the multihazard dimension are (1) the high computational costs for both multihazard risk quantification and system-level optimization and (2) the lack of capital cost databases of NPPs. To resolve these issues, this paper proposes an effective method that identifies the optimal multihazard capacity of NPPs using a multi-objective genetic algorithm and the two-stage direct quantification of fault trees using Monte Carlo simulation method, called the two-stage DQFM. Also, a capacity-based indirect capital cost measure is proposed. Such a proposed method enables NPP to achieve safety and cost-effectiveness against multi-hazard simultaneously within the computationally efficient platform. The proposed multihazard capacity optimization framework is demonstrated and tested with an earthquake-tsunami example.

• 대한교통학회지
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• 제8권1호
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• pp.5-15
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• 1990

As a result of the lack of methodology for the determination of navigational channel capacity and the consequence lack of effective management of traffic, navigational channels are often grossly underutilized or highly congested. The traditional rule of first-come-first-served admission of vessels to channels is not efficient as it assumes equal time intervals between entrance of consecutive vessels. A new vessel traffic management system is developed in this research and methodologies to measure the improvement in the channel capacity are developed. Methodology to measure the channel performances for three queue disciplines are developed. The effects of changes in major factors on the channel capacity model such as channel length, fleet mix and arrival rate, as well as changes in strategy are analyzed. Under given channel conditions, best strategy are recommended. Also, a method for effective stochastic channel capacity simulation was developed. The results of analysis and as ertions are compared with the results of simulation runs to prove their applicability.

• 한국수산과학회지
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• 제36권2호
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• pp.74-79
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• 2003

The functional properties such as a firming maintenance capacity for fermented vegetables, protein coagulation capacity antibacterial activity, calcium and peroxide absorption capacity of calcium powder of cuttle bone treated with acetic acid (ATC) were examined. In the Korean pickled cucumbers (20 days), the calcium content of ethanol insoluble solids was 5,264.9 mg/100 g and this value was higher than that of control (2,036.4 mg/100 g). Protein coagulation capacity of ATC was $0.9\%$ and its calcium absorption capacity was $49.3\%.$ The peroxide absorption capacity of ATC was shown $0-1.1\%$ range. Antibacterial activity was detected above $0.2\%.$ The ATC was effective in a firming maintenance of fermented vegetables (cucumber), coagulation capacities for soybean milk and antibacterial activity. The ATC was not effective in clarifying wastewater. Peroxide absorption capacity toward linoleic acid could not be checked by ATC, but its calcium absorption ratio was high compared to that of commercial calcium powder.

• Geomechanics and Engineering
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• 제31권2호
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• pp.223-235
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• 2022

Bearing capacity of shallow foundations is often determined for either dry or saturated soils. In some occasions, foundations may be subjected to external loading which is inclined and/or eccentric. In this study, the ultimate bearing capacity of shallow foundations resting on partially saturated coarse-grained cohesionless and fine-grained cohesive soils subjected to a wide range of combined vertical (V) - horizontal (H) - moment (M) loadings is rigorously evaluated using the well-established limit equilibrium method. The unified effective stress approach as well as the suction stress concept is effectively adopted so as to simulate the behaviour of the underlying unsaturated soil medium. In order to obtain the bearing capacity, four equilibrium equations are solved by adopting Coulomb failure mechanism and Bishop effective stress concept and also considering a linear variation of the induced matric suction beneath the foundation. The general failure loci of the shallow foundations resting on unsaturated soils at different hydraulic conditions are presented in V - H - M spaces. The results indicate that the matric suction has a marked influence on the bearing capacity of shallow foundations. In addition, the effect of induced suction on the ultimate bearing capacity of obliquely-loaded foundations is more pronounced than that of the eccentrically-loaded footings.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1272-1277
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• 2009

Since improved capacity for RC bridges has been required due to deterioration or increase in traffic, the deflection of cracked reinforced concrete slabs need to be reconsidered. Strengthening is known as the better way to improve capacity of bridges than reconstructing. In this paper, Fiber Reinforced Plastic (FRP) was introduced as one of the best strengthening methods for civil structures. The structures strengthened with FRPs can improve the strengthening capacity and serviceability. Therefore, CFRP sheet and Glass Fiber-Steel Composite Plate (GSP) in this research were used for strengthening slabs of RC bridges. Experimental data from the strengthening will be helpful to better understand the effect of the strengthening and effective flexural rigidity.