• Transactions of the KSME C: Technology and Education
• /
• v.5 no.2
• /
• pp.115-126
• /
• 2017

This paper proposes an accelerated life evaluation of drive shaft for the power train parts of special purpose vehicle. It is necessary the real load data of usage level driving load condition for life evaluation of power train parts, but we can't get the load spectrum data for evaluation in many case of special purpose vehicle. So, in this paper, the road load spectrum data for evaluation is created by modeling and simulation based on vehicle data and special road condition. The inverse power model is used for accelerated life test. The equivalent torque of load spectrum is achieved using the Miner's Rule. This paper also proposes the calibrated acceleration life test method for drive shaft. The fatigue test is performed through three stress levels. The lifetime at normal stress level is predicted by extrapolation, and is verified through comparison of experimental results and load spectrum data.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.13 no.1
• /
• pp.94-101
• /
• 1999

In this paper the problems associated with the switching surge of PWM inverter devices were analysed. As the application of ASD for efficient speed control of AC rmtors is increased, so is the rrntor and ASD-related failure increased. In the industrial rmtor awlications, the introduction of PWM drives can sometmes cause insulation breakdown between the phase windings due to high transient voltage peak. The motor cable length combined with the high switching frequency becomes more sensitive issue for proper drive operation. Effects of the cable length and high switching frequency influence both on rmtor and inverter. When the insulation level of rmtor winding is low, the failure probability caused by high peak voltage and fast voltage rise times(dv/dt) is high. Voltage refloctions are simulated far rmtor capacities, ASD and rise times and are presented graphically. The filtering techniques are discussed to reduce the rmtor terminal overvoltage and dv/dt in inverter fed AC rrntor drive systems. We confirmed that the lower motar capacity and rmtar insulation level, the shorter switching time and cable length and the higrer the probability of insulation breakdown .kdown .

• Journal of the Korean Institute of Landscape Architecture
• /
• v.40 no.1
• /
• pp.69-80
• /
• 2012

The garden has long served as away of thinking about nature and about culture and how each influences the other (Francis and Hester, 1990). This study, viewing the garden as a representation of the ideal, tried to seek for detailed aspects of the aforementioned ideal with the representative examples of Thomas Jefferson's gardens. Hidden behind his best known position as a politician was his other career: designer and creator of several gardens. Monticello, Academical Village, and Poplar Forest represented not only his ideals of national values like freedom, democracy and agrarian society, but also a yearning for the rural area and ideals for higher education realization. His personal desire and ideal are represented inside the spatial order, together with his ideals as a politician and the pioneer of new country. By representing the symbolic meaning metaphorically and restructuring it through a spatial scheme, Jefferson's ideal was admired and shared with visitors. In this way, Jefferson's gardens were practical stages to reveal his ideals.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.313-322
• /
• 2005

In this paper, High power factor electronic ballast using a double resonant Inverter for 250[W] MHD lamp is designed and implemented. Proposed electronic ballast is composed of configuration that is cascaded boost active PFC circuit as power factor corrector and half-bridge double resonant inverter Into two stage approach. Theoretical analysis of circuit and characteristics estimation is generally illustrated by using normalized parameter. To remove the phenomenon of acoustic resonance in the lamp, Simple frequency controller composed timer IC and driving IC is designed and employed on the ballast. The experimental results show that an high power factor electronic ballast using a double resonant inverter is operated stably.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.2
• /
• pp.952-958
• /
• 2011

Industrialization played an important role in modernization and the birth of modern architecture. The changes caused by the industrialization and people's faith in its output are reflected in an attempt to associate the concepts and process of architecture with industrialization. In the course of incorporating architecture into the industrialization process, it became necessary to understand the architecture from practical point of view connecting it directly with scientific technology rather than in the context of historical tradition in the past. Understanding architecture as a kind of industrial production signifies two concepts. One is regarding perception of architectural outputs. The other is regarding the intention to proceed architectural process as a process of industrial production. The purpose of this study is to review the changes in the architecture influenced by industrialization from post-industrialization through early modern period and to analyze its significance and influence.

• Journal of the Korean association of regional geographers
• /
• v.10 no.3
• /
• pp.554-567
• /
• 2004

Since the 1980s, the academic interests on the regional geography have been renewed. This trend is usually called 'Renaissance' of the regional geography. Given this context, to explore diverse theories and methodologies in the regional geography is of much significance. Particularly, to examine the regional geography in Germany widens the understanding of not only the history, strength, and weakness of the regional geography, but also the discipline's status in the field of geography. This paper discusses the regional geography in Germany before World War II, focusing on varieties of theories and methods as well as the historical trajectory of the German regional geography. This discussion may well be significant in that 'Laenderkunde' became an important paradigm in the discipline of geography in Germany during the pre-World War II period.

• Science of Emotion and Sensibility
• /
• v.19 no.2
• /
• pp.67-78
• /
• 2016

The purpose of this study was to investigate relationships among the older drivers' subjective evaluation and objective performances for driving ability, mobility and subjective well-being. Scores for mobility and subjective well-being were obtained using questionnaires. Diagram-based driving scenarios and driving simulation were used to measure subjective and objective driving abilities, respectively. The results can be summarized as followings. First, subjective evaluation scores of driving ability but not objective driving performance significantly correlated with mobility. Second, the higher level of mobility predicted higher life satisfaction, higher positive affectivity, and lower negative affectivity. Third, the older driver's higher scores of subjective driving ability induced higher level of mobility, which, in turn, increased life satisfaction and positive affectivity but lower negative affectivity. The results suggested that subjective rather than objective ability for driving is more important in determining the level of old driver's subjective well-being.

• School Mathematics
• /
• v.5 no.3
• /
• pp.361-384
• /
• 2003

The purpose of this study was to investigate students' problem solving process based on the model of IDEAL if they learn to solve word problems of simultaneous linear equations through structure-representation instruction. The problem solving model of IDEAL is followed by stages; identifying problems(I), defining problems(D), exploring alternative approaches(E), acting on a plan(A). 160 second-grade students of middle schools participated in a study was classified into those of (a) a control group receiving no explicit instruction of structure-representation in word problem solving, and (b) a group receiving structure-representation instruction followed by IDEAL. As a result of this study, a structure-representation instruction improved word-problem solving performance and the students taught by the structure-representation approach discriminate more sharply equivalent problem, isomorphic problem and similar problem than the students of a control group. Also, students of the group instructed by structure-representation approach have less errors in understanding contexts and using data, in transferring mathematical symbol from internal learning relation of word problem and in setting up an equation than the students of a control group. Especially, this study shows that the model of direct transformation and the model of structure-schema in students' problem solving process of I and D stages.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.6
• /
• pp.4216-4227
• /
• 2015

In this study, a model is developed based on Life Cycle Energy Analysis (LCEA) method with Genetic Algorithm (GA) to determine optimal diameter of Water Distribution System (WDS). For hydraulic analysis the EPANET2.0 program is linked with developed model, pipe-aging equation and pipe-breakage equation are built in to developed model to simulate pipe change through life cycle. The model is then applied to two sample WDSs for optimal energy design. After determining optimal diameter for each WDS, the total cost is calculated based on determined diameter and compared with well-known optimal diameter set of each WDS. Results show that optimal energy design of WDSs through the developed model can be an alternative option for optimal design of WDSs for reducing energy with lower in cost.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.22 no.2
• /
• pp.26-33
• /
• 2018

This paper presents experimental and analytical results on flexural behavior of flexural members made of SIFCON. Twelve SIFCON beams were subjected to bending tests and their flexural behavior was evaluated. Experimental variables included steel fiber type, presence of tensile reinforcement, and height of section. The specimens using Type-B steel fibers, which had better pullout resistance than Type-A steel fibers, showed flexural failure behavior without shear failure. The aspect ratio of steel fiber had a great influence on the behavior of SIFCON beams without tensile steel, however the effect on the behavior of SIFCON beams was negligible. In addition, the flexural strength equation for SIFCON was proposed in the study. The mean and standard deviation of the ratios of the predicted value to the experimental value are 1.02 and 0.04, respectively. Therefore, the proposed flexural strength equation can be useful for the design and performance evaluation of SIFCON beam.