• Journal of KIISE
• /
• v.42 no.11
• /
• pp.1410-1422
• /
• 2015

In order to design a system, software developers use an object model such as the UML class diagram. Object-Relational Transformation Methodology (ORTM) is a methodology to transform the relationships that are expressed in the object model into relational database tables, and it is applied for the implementation of the designed system. Previous ORTM studies have suggested a number of transformation methods to represent one relationship. However, there is an implementation problem that is difficult to apply because the usage criteria for each transformation method do not exist. Therefore, this paper proposes a binary decision diagram-based modeling rule for each relationship. Hence, we define the conditions for distinguishing the transformation methods. By measuring the query execution time, we also evaluate the modeling rules that are required for the verification. After evaluation, we re-define the final modeling rules which are represented by propositional logic, and show that our proposed modeling rules are useful for the implementation of the designed system through a case study.

• Journal of Power Electronics
• /
• v.13 no.4
• /
• pp.516-527
• /
• 2013

This paper presents a new overall system for state-of-available-power (SoAP) prediction for a lithium-ion battery pack. The essential part of this method is based on an adaptive network architecture which utilizes both fuzzy model (FIS) and artificial neural network (ANN) into the framework of adaptive neuro-fuzzy inference system (ANFIS). While battery aging proceeds, the system is capable of delivering accurate power prediction not only for room temperature, but also at lower temperatures at which power prediction is most challenging. Due to design property of ANN, the network parameters are adapted on-line to the current battery states (state-of-charge (SoC), state-of-health (SoH), temperature). SoC is required as an input parameter to SoAP module and high accuracy is crucial for a reliable on-line adaptation. Therefore, a reasonable way to determine the battery state variables is proposed applying a combination of several partly different algorithms. Among other SoC boundary estimation methods, robust extended Kalman filter (REKF) for recalibration of amp hour counters was implemented. ANFIS then achieves the SoAP estimation by means of time forward voltage prognosis (TFVP) before a power pulse occurs. The trade-off between computational cost of batch-learning and accuracy during on-line adaptation was optimized resulting in a real-time system with TFVP absolute error less than 1%. The verification was performed on a software-in-the-loop test bench setup using a 53 Ah lithium-ion cell.

• The KIPS Transactions:PartD
• /
• v.13D no.7 s.110
• /
• pp.959-970
• /
• 2006

With the progress of home network technologies, the importance of the home network middleware for control and management of the digital appliances is increasing. Furthermore, by the technological growth of the AV equipments and the popularization of video contents, IEEE1394 for the transmission of AV data has spread fast. However, DLNA(Digital Living Network Alliance), which is a standard of the home network middleware, does not consider the transmission of AV data over IEEE1394. In this paper, we describe the problem occurring when the AV contents are transmitted over IEEE1394 in DLNA and propose the scheme for transmission of AV contents over IEEE1394. In addition, by the verification test of DLNA compatibility, we show that our proposed scheme can provide the share of AV contents without regard to the manufactures and transmission media.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.9
• /
• pp.414-423
• /
• 2020

Fiber-reinforced polymer (FRP) laminate sheets, which are lightweight with high strength, are commonly used to reinforce concrete structures. The bonding strength is vital in structural design. Therefore, experiments and analytical studies with differing variables (concrete compressive strength and tensile strength, the elastic modulus of concrete and FRP, thickness of concrete and FRP, width of concrete and FRP, bond length, effective bond length, fracture energy, maximum bond stress, maximum slip) have been conducted to obtain an accurate numerical model of the bond strength between an FRP sheet and concrete. Although many models have been proposed, no validated model has emerged that could be used easily in practice. Therefore, this study analyzed the parameters that influence the bond strength that were used in 23 of the proposed models (Khalifa model, Iso model, Maeda model, Chen model, etc.) and compared them to the test results of 188 specimens via the numerical results of each model. As a result, an easy-to-use practical model with a simple and high degree of expression was proposed based on the Iso model combined with the effective bond length model that was proposed by Holzenkӓmpfer.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.24 no.2
• /
• pp.60-67
• /
• 2020

Recently, many studies have been conducted on the structural behavior of HPFRCC, but most of the studies focused on the flexural behavior while studies on the shear behavior are limited. In this study, a model has been developed to reasonably predict the shear strength of a HPFRCC beam without stirrups. To develop the model, a HPFRCC beam was simply idealized with upper & lower chords resisting bending moment and a web shear element resisting shear forces. Then, taking into the account of the tensile behavior of HPFRCC, the main diagonal compressive strut angle and shear stress of the web shear element were evaluated on shear failure. Then, the shear strength of the HPFRCC beam could be evaluated. For the verification of the proposed model, the predictions by the proposed model were compared with the test results of 48 HPFRCC beams exhibiting shear failure. The results showed that the proposed model reasonably predicted the actual shear strength with an average of 1.045 and CoV of 0.125. This study are expected to be useful for related researches and design of members or structures to which HPFRCC is applied.

• The Journal of the Korea Contents Association
• /
• v.6 no.12
• /
• pp.216-225
• /
• 2006

Teaching methods should focus on enabling the students to adopt an open mind towards new experiences and to be flexible to change. Moreover, their purpose lies in encouraging the students to build their ability to discern values so that they can make the right decisions when they are at a crossroad. However, traditional teaching methods were centered on textbooks and on the teachers. This type of teaching method needs to change so that the new teaching method will focus on the students themselves, taking levels of individual students into consideration to enable development of their creativity in line with the demands made during the 21st century, an era of information and globalization. Projected learning method is appropriate for the Physical Education (PE) classes where various activities aim to increase the level of cooperation among students and their investigative skills. Moreover, PE classes pay special attention to the practical aspect. Accordingly, this research makes recommendations for the class execution methods based on projected learning by improving the curriculum for the PE classes, and the effect of these methods are subject to verification.

• Journal of Digital Convergence
• /
• v.15 no.3
• /
• pp.211-219
• /
• 2017

Among government projects for reduction of coastal disaster, coastal maintenance project stage 1(2000~2009) and stage 2(2010~2019) to reduce coastal erosion and sedimentation are currently under process. In performing the coastal maintenance projects, it is necessary to install artificial concrete armor units for coastal protection. Presently in Korea, products manufactured in Japan are applied to the site, or blocks self-developed by the construction firms are installed. However, there is a lack of technical reviews such as verification of hydraulic characteristics, securing the stability and design techniques. This study is intended to develop waterfront shore protection blocks with good accessibility of people and excellent coastal disaster reduction and protection capability. Through this study, hydraulic characteristics and stability coefficients of shore protection blocks could be drawn.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.4 no.3 s.14
• /
• pp.51-60
• /
• 2004

Urban flood damage has been caused by drainage deficiency. One of the methods to solve this problem is to construct detention basin and Pumping station and to pump out the water to the river. However, because of rapid urbanization, the capacity of drainage pipelines is sometimes not sufficient enough during the rainy season. Therefore, even though we have enough pumping stations, the inflow of surface water never reaches to the detention area, causing floods in urban area. This research is to find improvement of urban drainage system, estimating drainage pipeline risk. Also, eight models for a computer program were developed for practical use. The models were verified changing precipitation duration, intensity, design period, time distribution model, and etc. This verification was processed focusing that the model can regulate the water level in the detention basin and minimize the effect downstream. As a result Fuzzy models were found to be efficient to lower the water level in detention basin, and decreased about 8 cm in water level of downstream.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.3
• /
• pp.228-239
• /
• 2016

CNUSAIL-1 is a 3U-sized cube satellite with $4m^2$ small solar sail which is currently being developed at the Chungnam National University. The primary purpose of the CNUSAIL-1 is successful sail deployment in LEO and its operation for investigating its effect on satellite orbit and attitude as well as performing de-orbiting using the sail membranes as drag sail at the final phase. The system design and mechanism of solar sail deployment is introduced, and optical and tensile tests are carried out for the material of membranes and booms for its safety and performance verification. The ground test is carried out to verify its performance for sail deployment and satellite through comparison between folding methods by determining its folding patterns, thickness of spiral spring and angular velocity measurement in a low-friction environment.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.23 no.1
• /
• pp.65-72
• /
• 2013

This case study presents a practical method to reduce resonant vibration of large vertical pumps. The pumps are driven at 400 rpm rated speed by induction motor. The vibration was not significantly large when operated at this rated speed. Large vibration was occurred when the pump was operated below the rated speed for flow control. Due to the large vibration resonance, variable speed operation of the pump was not possible for several months at worst cases. To find an efficient vibration control method, the flexural responses of pumps for both normal and transient operations were measured. The measured modal characteristics were compared with those of finite element analysis. When the pump was operated at a specific rpm, the natural mode whose resonance frequency is twice the rotating angular speed induced the large vibration. The retrofit utilizing stiffeners to reduce this resonant vibration were performed. Effects of designed stiffeners on reducing vibration were validated through tests after actual installation.