• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권10호
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• pp.4231-4245
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• 2020

Non-orthogonal multiple access (NOMA) is widely studied in both academia and industry due to its high spectral efficiency over orthogonal multiple access (OMA). To effectively improve spectrum efficiency, an amplify-and-forward (AF) cooperative NOMA system is proposed as well as a novel detection scheme is proposed, in which we first perform successive interference cancellation (SIC) twice at U1 for the two signals received from two time slots to remove interference from symbol 2, then two new signals apply max ratio combining (MRC). In addition, a closed-form upper bound approximation for the ergodic capacity of our proposed system is derived. Monte-Carlo simulations and numerical analysis illustrate that our proposed system has better ergodic capacity performance than the conventional cooperative NOMA system with decode-forward (DF) relay, the conventional cooperative NOMA system with AF relay and the proposed AF cooperative NOMA system in [16]. In addition, we can see that ergodic capacity of all NOMA cooperative systems increase with the increase of transmit SNR. Finally, simulations display that power allocation coefficients have little effect on ergodic capacity of all NOMA cooperative systems. This is due to this fact that ergodic capacity of two symbols can be complementary with changing of power allocation coefficients.

• Geomechanics and Engineering
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• 제13권5호
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• pp.825-844
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• 2017

This study aimed to find out the pullout capacity of inclined strip anchor plate embedded in anisotropic and nonhomogeneous fully saturated cohesive soil in undrained condition. The ultimate pullout load has been found out by using numerical lower bound finite element analysis with linear programming. The undrained pullout capacity of anchor plate of width B is determined for different embedment ratios (H/B) varying from 3 to 7 and various inclination of anchor plates ranging from $0^{\circ}$ to $90^{\circ}$ with an interval of $15^{\circ}$. In case of anisotropic fully saturated clay the variation of cohesion with direction has been considered by varying the ratio of the cohesion along vertical direction ($c_v$) to the cohesion along horizontal direction ($c_h$). In case of nonhomogeneous clay the cohesion of the undrained clay has been considered to be increased with depth below ground surface keeping $c_v/c_h=1$. The results are presented in terms of pullout capacity factor ($F_{c0}=p_u/c_H$) where $p_u$ is the ultimate pullout stress along the anchor plate at failure and $c_H$ is the cohesion in horizontal direction at the level of the middle point of the anchor plate. It is observed that the pullout capacity factor increases with an increase in anisotropic cohesion ratio ($c_v/c_h$) whereas the pullout capacity factor decreases with an increase in undrained cohesion of the soil with depth.

• The Journal of Korean Physical Therapy
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• 제31권4호
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• pp.248-253
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• 2019

Purpose: To improve pulmonary function and decrease in balance ability with increasing forward head position and vertebral curvature, we applied Figure-8 brace to confirm the immediate effect on vital capacity and balance and to see if it is applicable. Methods: A total of 34 elderly women aged 65 or older and young women in their 20s with FHP were screened to measure vital capacity, measuring the forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), and measuring the foot pressure to see the change in balance. For statistical analysis, the difference between pre and post values was compared using pared t-test. Results: As a result of vital capacity measurements, there was no significant difference between FEV1 and FVC for women over 65 years old (p>0.05). Young women in their 20s had no significant difference in FEV1 (p>0.05), and FVC had significant differences (p<0.05). In measuring foot pressure to measure balance, both women aged 65 and above and young women in their 20s had a significant decrease in anterior foot pressure, and a significant increase in posterior foot pressure (p<0.05). Conclusion: The results of this study did not positively affect the vital capacity of elderly women with FHP. However, the significant increase in vital capacity of young women in their 20s suggests that contraction of the abdominal muscle is necessary during forced expiration. Therefore, it is believed that proper application and therapeutic interventions should be combined when applying Figure-8 brace.

• Advances in concrete construction
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• 제13권 2호
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• pp.163-181
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• 2022

To study the mechanical properties of steel reinforced recycled concrete (SRRC) filled circular steel tube columns under eccentric compression loads, this study presents a finite element model which can simulate the eccentrically compressed columns using ABAQUS software. The analytical model was established by selecting the reasonable nonlinear analysis theory and the constitutive relationship of materials in the columns. The influences of design parameters on the eccentric compressive performance of columns were also considered in detail, such as the diameter-thickness ratio of circular steel tube, replacement percentage of recycled coarse aggregate (RCA), slenderness ratio, eccentricity, recycled aggregate concrete (RAC) strength and steel strength and so on. The deformation diagram, stress nephogram and load-displacement curves of the eccentrically compressed columns were obtained and compared with the test results of specimens. The results show that although there is a certain error between the calculation results and the test results, the error is small, which shows the rationality on the numerical model of eccentrically compressed columns. The failure of the columns is mainly due to the symmetrical bending of the columns towards the middle compression zone, which is a typical compression bending failure. The eccentric bearing capacity and deformation capacity of columns increase with the increase of the strength of steel tube and profile steel respectively. Compared with profile steel, the strength of steel tube has a greater influence on the eccentric compressive performance of columns. Improving the strength of RAC is beneficial to the eccentric bearing capacity of columns. In addition, the eccentric bearing capacity and deformation capacity of columns decrease with the increase of replacement percentage of RCA. The section form of profile steel has little influence on the eccentric compression performance of columns. On this basis, the calculation formulas on the nominal eccentric bearing capacity of columns were also put forward and the results calculated by the proposed formulas are in good agreement with the test values.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.381-388
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• 1999

The existing methods for installation of long steel pipe pile have some uneconomical problems such as increase of installation cost and period due to the welding of two piles and removal of soil plug, and decrease of driving efficiency due to the increase of driving resistance by time effect during the welding of piles and removal of soil plug, etc. Thus, in this study, new installation method for long steel pipe pile is suggested to work out the existing problems, and calibration chamber tests are peformed to investigate both driving and economical efficiency for the suggested method. The test results showed that the new installation method has increase bearing capacity as well as reduce installation cost and period for long steel pipe piles as compared with existing methods.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.142-144
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• 2008

The Former High Efficiency Inverter(the power restoration process) system process has advantage which is the energy reduction rather than the Former Inverter(the resistence damping process), However, under repair and remodeling, the power facilities capacity is not easy to increase that the former High Efficiency Inverter needs to increase the Power Facilities Capacity of 20~30% than the Inverter(the resistence damping process) so Therefore we are going to suggest the system which is not going to make an increase the power facilities capacity and is applicable the High Efficiency Inverter.

• 열처리공학회지
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• 제11권1호
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• pp.1-9
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• 1998

The objective of this study is to investigate the effect of solution-treatment temperature on the microstructure and damping capacity of a martensitic Fe-7%Ni-0.4%C alloy. The size of lath increased from $0.3{\mu}m$ to $0.55{\mu}m$ with increasing the solution-treatment temperature from 700 to $1100^{\circ}C$. In addition, the size of block, packet, and austenite grain had tendency to increase with increasing solution-treatment temperature. The damping capacity of the Fe-7%Ni-0.4%C martensitic alloy decreased with increasing the solution treatment temperature. The reason is not attributed to the increase in the size of lath, block, packet, and austenite grain, but to the increase in vacancy concentration which hinders dislocation motion.

• 한국시스템다이내믹스연구
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• 제12권4호
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• pp.93-124
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• 2011

The introduction of competition in the generation of electricity has raised the fundamental question of whether markets provide the right incentives for the provision of the capacity needed to maintain system reliability. Capacity mechanisms are adopted around the world to guarantee appropriate level of investment in electricity generation capacity. In this study, we discuss these approaches and analyze the capacity pricing mechanisms from the adequacy perspective. We conclude that the design of capacity mechanism is very important to decrease electricity spot price and increase total electric capacity. Specifically, the constant of capacity pricing mechanism made a difference to the performance of electricity market. However, the slope of capacity price mechanism is better than the constant of that in improving performance of electricity market.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.831-835
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• 2005

In a signal control of the railway system, the first objective is to guarantee a safety of the train operation, and the second is to increase a frequency(a capability of the transportation) of the train operation. In order to express the capability of the transportation a terminology what is called a railroad line capacity is employed. The railroad line capacity means a maximum frequency of the train operation in a possible schedule of the one way operation for one day. During the last several years an improvement in the facilities of the train operation (railroad line extension, improvement in the stations, improvement in the signal facilities) has been achieved to increase the railroad line capacity. In this paper the authors deal with the case analysis which try to shorten headway and which has an impartible relation with increasing of the railroad capacity

• 대한산업공학회지
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• 제32권2호
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• pp.104-110
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• 2006

When a new facility such as automobile assembly line is designed, computer simulation is often used to estimate its actual throughput level. If it falls short of the target throughput level, then the design must be modified to increase the throughput capacity. For complex facilities having parallel processes and network of material flows, the modification procedure is not trivial. Even if the capacity of a particular bottleneck process is increased, the target throughput may not be achieved because the bottleneck may move to another process. Furthermore, each process has a different set of options with different cost to increase the capacity. In this study, we present a systematic procedure of determining the cost-effective set of options which achieves the target throughput.