• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.2A
• /
• pp.259-267
• /
• 2008

The ultimate strengths of reinforced concrete deep beams are governed by the capacity of the shear resistance mechanism composed of concrete and shear reinforcing bars, and the structural behaviors of the beams are mainly controlled by the mechanical relationships according to the shear span-to-effective depth ratio, flexural reinforcement ratio, load and support conditions, and material properties. In this study, a simple indeterminate strut-tie model reflecting all characteristics of the ultimate strengths and complicated structural behaviors is presented for the design of simply supported reinforced concrete deep beams. In addition, a load distribution ratio, defined as a magnitude of load transferred by a vertical truss mechanism, is proposed to help structural designers perform the design of simply supported reinforced concrete deep beams by using the strut-tie model approaches of current design codes. In the determination of a load distribution ratio, a concept of balanced shear reinforcement ratio requiring a simultaneous failure of inclined concrete strut and vertical steel tie is introduced to ensure the ductile shear failure of reinforced concrete deep beams, and the prime design variables including the shear span-to-effective depth ratio, flexural reinforcement ratio, and compressive strength of concrete influencing the ultimate strength and behavior are reflected upon based on various and numerous numerical analysis results. In the companion paper, the validity of presented model and load distribution ratio was examined by employing them to the evaluation of the ultimate strengths of various simply supported reinforced concrete deep beams tested to failure.

• Journal of the Korean Geotechnical Society
• /
• v.40 no.2
• /
• pp.29-40
• /
• 2024

This study aimed to evaluate the swelling behavior characteristics of KJ-II buffer blocks by performing numerical analysis of swelling pressure measurement experiments using the nonlinear elasticity model of COMSOL Multiphysics. The analysis was conducted under boundary conditions that included isotropic constraints and water injection pressure, mirroring the experimental settings. Validation of the numerical model was achieved by comparing its outputs with experimental results. The validated model was then used to simulate swelling deformations under unconfined conditions and to analyze swelling pressure as influenced by dry density and the geometric shape of the buffer material. The results accurately represented the swelling deformation observed during the saturation process and demonstrated that swelling pressure increases with higher dry density. Moreover, simulations concerning the geometric shape of the buffer material indicated a markedly faster rate of pressure increase in U-shaped samples compared to cylindrical ones. Analysis suggested that stress manifested preemptively near the internal edges of U-shaped samples during saturation. To enhance the simulation's fidelity to actual buffer material behavior, further refinement of the analysis model using a nonlinear elasticity model is recommended.

• The Journal of Society for e-Business Studies
• /
• v.12 no.1
• /
• pp.41-71
• /
• 2007

Researchers have continuously investigated the issues of customer satisfaction, customer loyalty, and repurchase intention of customers in Internet shopping malls, a fast growing e-bisiness model in Korea. At present, most Internet shopping malls in Korea offer similar services to their customers. This has caused intense industry competition, and the Internet shopping malls have made significant investments into their websites in order to remain attractive to their customers. This research examines the relationships among website charateristics, customer satisfaction, loyalty, and repurchase intention. Website characteristics include context, commerce, connection, communication, contents, community, and customization. We have used data from a field study of 662 individuals to test the proposed model. The results of this research show that among the 7 website characteristics, context, communication, content, and commerce are the significant determinants of customer satisfaction. In turn, customer satisfaction increases customer loyalty and repurchase intention. These findings have important theoretical and practical implications, which are discussed in the paper.

• Journal of Korean Society of Steel Construction
• /
• v.21 no.6
• /
• pp.597-608
• /
• 2009

In this paper, large-deformation elasto-plastic analysis of space frames that considersjoint connection properties is presented. This method is based on the large-deformation formula with finite rotation, which was developed initially for elastic systems, and is extended herein to include the elasto-plastic effect and the member joint connection properties of semi-rigid what?. The analytical method was derived from the Eulerian concept, which takes into consideration the effects of large joint translations and rotations. The localmember force-deformation relationships were obtained from the beam-column approach, and the change caused by the axial strain in the member chord lengths and flexural bowing were taken into account. The effect of the axial force of the member on bending and torsional stiffness, and on the plastic moment capacity, is included in the analysis. The material is assumed to be ideally elasto-plastic, and yielding is considered concentrated at the member ends in the form of plastic hinges. The semi-rigid properties of the member joint connection are considered based on the power or linear model. The arc length method is usedto trace the post-buckling range of the elastic and elasto-plastic problems with the semi-rigid connection. A sample non-linear buckling analysis was carried out with the proposed space frame formulations to demonstrate the potential of the developed method in terms of its accuracy and efficiency.

• The Journal of the Korea Contents Association
• /
• v.22 no.10
• /
• pp.291-308
• /
• 2022

The purpose of this study is to suggest an effective marketing method for product advertising. With regards to this, 148 copies of survey data were collected from consumers, and the hypothesis of this study was verified using SPSS 25.0. The results revealed that (1) Human Brand attractiveness had a positive effect on Human Brand attachment among the products of low involvement. (2) The uniqueness and the intimacy of Human Brand had a positive effect on Human Brand attachment among the products of high involvement. Through this study, the effect of reliability, expertise, attractiveness, uniqueness, and intimacy among human brand characteristics on human brand attachment, human brand attitude, and product purchase intention was confirmed, and it was also possible to confirm the difference in influence on human brand characteristics and purchase intention according to the product characteristics involved. This study has expanded the research scope of Human Brand, which has been studied mainly by entertainers and entrepreneurs, to sports stars and through empirical analysis, it has tried to identify influencing factors to improve purchasing intent based on high and low-contention characteristics of advertising products.

• Information Systems Review
• /
• v.22 no.3
• /
• pp.143-156
• /
• 2020

Price promotion is one of the most frequently marketing strategies with a long history. According to various studies, the effect of price promotion is controversial. Some studies have argued that price promotion has a positive effect, while others have found that it has no effect or rather has a negative effect. This study aims to examine the effect of price promotion in a subscription-based service. First, we check the effect of price promotion on the repurchase of the consumer. And we investigate how this effect varies depending on the characteristics of the consumer. Using the data from one of the music streaming service in South Korea, the effect of consumers' price promotion experience, demographic characteristics, and behavioral characteristics on their repurchase is analyzed through logistic regression analysis. As a result of the study, it is found that consumers' experience of price promotion has a positive effect on repurchase. In addition, the positive effect of price promotion is relatively greater in younger and female consumers. This study has implications in that it not only confirmed the positive effect of price promotion in a subscription-based environment but also empirically confirmed that the characteristics of consumers should be considered when performing price promotion.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.13 no.3
• /
• pp.50-57
• /
• 2009

A gas mechanical pulsator is developed for the study of combustion instabilities in various combustors such as LRE combustor. First, it shows that the mass flow rates and the perturbation frequencies can be successively controlled by the inlet pressure and the rotating speed of a rotating disk with many holes. Second, the device is used as an acoustic amplification source as a substitute for the speaker in the previous acoustic tests and its results show almost the same resonant frequency and damping characteristics compared with the previous results. In conclusion, the result shows that it can be used as a substitute for a speaker in the studies of LRE combustion instabilities, which has a flow and no limitation of amplification, and a device for making a perturbation source in gas flow.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.4C
• /
• pp.362-369
• /
• 2007

APSK (Amplitude Phase Shift Keying) digital modulation is characterized by the circular positioning of the transmission symbols in the constellation diagram. Due to such structural characteristics, the peak-to-average power ratio of the APSK modulation is lower than that of the QAM (Quadrature Amplitude Modulation), and the amount of performance degradation over nonlinear channels can be mitigated. The APSK modulation scheme has recently been adopted as satellite communication system standards including the DVB-S2 (Digital Video Broadcasting - Satellite, Version 2). In this paper, a BER (Bit Error Rate) upper bound approximation formula is derived using the channel model with the output power saturation characteristics, and its accuracy is demonstrated. Using the derived formula, the input power level that minimizes the BER is determined. The optimized performance based on the radii ratio of the 16APSK constellation and the channel saturation level is also presented.

• The Journal of Korean Association of Computer Education
• /
• v.16 no.3
• /
• pp.99-105
• /
• 2013

The FPGA-based emulation is an essential step in ASIC design for validation. For emulation with maximal frequency, it is crucial to understand the FPGA characteristics. This paper attempts to analyze the performance characteristics of the modern FPGAs from renowned vendors, Xilinx and Altera, with a case study utilizing various adders and MIPS CPU. Unlike the common wisdom, ripple-carry adder (RCA) does not utilize the inherent carry-chain inside FPGAs when structurally designed based on 1-bit adders. Thus, the RCA shows the inferior performance to the other types of adders in FPGAs. Our study also reveals that FPGAs from Xilinx exhibit different characteristics from the ones from Altera. That is, the prefix adder, which is optimized for speed in ASIC design, shows the poor performance on Xilinx devices, whereas it provides a comparable speed to the IP core on Altera devices. It suggests that error-prone manual change of the original design can be avoided on Altera devices if area is permitted. Experiments with MIPS CPU confirm the arguments.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.11
• /
• pp.1483-1490
• /
• 2011

Electro-hydrostatic actuators(EHAs), which are usually composed of a direct motor-driven hydraulic pump and a cylinder, have been widely adopted as aircraft actuation systems because of their benefits in terms of improved efficiency, weight savings and the fact that they use a standalone power source. Since the recent trend in construction vehicles has been focus on energy savings in their hydraulic systems, EHAs are expected to be potential substitutes for conventional power transmission, since they are capable of energy recovery as well as highly efficient pump control. In this paper, the start and stop characteristics of EHAs were investigated through cracking pressure analysis of the pilot-operated check valve(PCV), which enables the cylinder to standstill against an external load with no holding effort from the hydraulic pump. A mathematical model that includes the load dynamics and the EHA's internal hydraulic circuit was derived for simulation with the MATLAB Simulink package. This model verified the PCV's opening and closing sequence, which in turn affects the EHA's start and stop characteristics.