• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.147-179
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• 2002

The important role of observational method in geotechnical engineering are emphasized together with the direction of future development, concerning successful application of the technique on the site investigation, design and feed back at various construction stages. Case histories on the application of feed back are introduced in order to achieve the most economical and reliable construction for tunnel, rock slope and deep excavations through feed back system at design and construction stages. Also the limitations and advantages of the observational method and the role of feed back system are discussed for construction of tunnel, rock slope and deep excavation in hard ground such as layered ground conditions including weathered, soft and hard rocks.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.76-79
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• 1999

A study on simulation using Matlab shows the dynamic condition of a beam on feed-back with encorder. A controller for rapid response interpreted the stability on simulation with pole-placement technique. The effect of response was considered feed-back gain. The result of feed-back is described that various feed-back coefficient shows stable controll systems. It would be expected each result according to controllers.

• Journal of the Korean Institute of Telematics and Electronics
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• v.15 no.3
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• pp.7-10
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• 1978

A method of full wave rectification is proposed which is accomplished by an inverter circuit including R-feed back. Both halves of the input cycle can be presented in the out put by composing a conductive half cycle and an inactive half cycle substituted by feed back in the cut off state.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.595-602
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• 2023

Feed processing methods can substantially enhance the nutrient value of feed. The aim of our study was to compare the effects of mash or crumble feed on growth performance, nutrient digestibility, back-fat thickness, and carcass quality of growing-finishing pigs. In total, 50 ([Landrace × Yorkshire] × Duroc) growing pigs with initial body weight of 46.24 ± 3.57 kg were randomly assigned to two dietary treatment groups. The two dietary treatments were: 1) mash and 2) crumble feed forms for 14 weeks of trials. Five replication pens per treatment, comprised five pigs (2 males and 3 females) each. Growth performance, nutrient digestibility, back-fat thickness, and carcass quality were observed at different weeks. There were no significant differences in growth performance, nutrient digestibility, back-fat thickness, and carcass quality throughout the experimental trial. Further study is required to understand the effects of mash and crumble feed on growing-finishing pigs.

• Journal of information and communication convergence engineering
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• v.4 no.4
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• pp.170-173
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• 2006

Recently, with increasing efficiency of DSC (photo-electrochemical using a nano-particle), The Performance of DSC solar generation system also needs improvement. The approach consists of a Fly-back DC-DC (transfer ratio 1:10) converter to boost the DSC cell voltage to 300VDC. The four switch (MOSFET) inverter is employed to produce 220V, 60Hz AC outputs. High performance, easy manufacturability, lower component count., safety and cost are addressed. Protection and diagnostic features form an important part of the design. Another highlight of the proposed design is the control strategy, which allows the inverter to adapt to the: requirements of the load as well as the power source. A unique aspect of the design is the use of the DSP TMS320LF2406 to control the inverter by current and voltage feed-back. Efficient and smooth control of the: power drawn from the DSC Cell is achieved by controlling the front end DC-DC converter in current mode.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.445-456
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• 2010

Massive underground excavation can be carried out recently due to the technical development of the excavation for retaining wall. Feed-back analysis using field measurement results is recommended to secure the stability of the construction because calculated values at stages of the design and the construction are uncertain. Reinforcement plan should be established based on the result of it. This study deals with the underground excavation site, which is under construction and is close to structure(subway) at downtown area. The result of feed-back analysis on the measurement data of displacement at multi-soil layers was reflected to make a plan for safe construction. This case study can be useful information for contingency plan on abnormal displacement which can be occurred at similar underground excavation.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.482-485
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• 2002

The boom of housing market lead to build a lot of apartment houses concentrated on the metropolitan area and developing new city in 1980's made 2,000,000 houses. In this time, quality standards could not be satisfied with consumers' desire due to the policy about excessive supply and come from unexpected defects in the complected buildings. In $1980's\~1990's$, It would be performed on the study for defect prevention in apartment houses. It has contributed in no way to the reduction at the rate of the defect outbreak and the solution of consumers' dissatisfaction by flaws. The reason is that the study related defects is not linked and applied by the managing and controlling system, Therefore, the study will be analyzed out defect information occurred on apartment houses of domestic construction and classified by type features. As a result, it will suggest web-based feed-back system for getting systematic information and the practical use.

• Smart Structures and Systems
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• v.3 no.2
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• pp.147-172
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• 2007

The present paper is concerned with the design of distributed sensors and actuators. Strain type sensors and actuators are considered with their intensity continuously distributed throughout a continuous structure. The sensors measure a weighted average of the strain tensor. As a starting point for their design we introduce the concept of collocated sensors and actuators as well as the so-called natural output. Then we utilize the principle of virtual work for an auxiliary quasi-static problem to assign a mechanical interpretation to the natural output of the sensors to be designed. Therefore, we take the virtual displacements in the principle of virtual work as that part of the displacement in the original problem, which characterizes the deviation from a desired one. We introduce different kinds of distributed sensors, each of them with a mechanical interpretation other than a weighted average of the strain tensor. Additionally, we assign a mechanical interpretation to the collocated actuators as well; for that purpose we use an extended body force analogy. The sensors and actuators are applied to solve the displacement tracking problem for continuous structures; i.e., the problem of enforcing a desired displacement field. We discuss feed forward and feed back control. In the case of feed back control we show that a PD controller can stabilize the continuous system. Finally, a numerical example is presented. A desired deflection of a clamped-clamped beam is tracked by means of feed forward control, feed back control and a combination of the two.

• Journal of Magnetics
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• v.22 no.1
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• pp.34-42
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• 2017

Material defects in the Steam Generator Tubes (SGT) of sodium cooled fast breeder reactor (PFBR) can lead to leakage of water into sodium. The water and sodium reaction will lead to major accidents. Therefore, the examination of steam generator tubes for the early detection of defects is an important requirement for safety and economic considerations. In this work, the Magnetic Flux Leakage (MFL) based Non Destructive Testing (NDT) technique is used to perform the defect detection process. The rectangular notch defects on the outer surface of steam generator tubes are modeled using COMSOL multiphysics 4.3a software. The obtained MFL images are de-noised to improve the integrity of flaw related information. Grey Level Co-occurrence Matrix (GLCM) features are extracted from MFL images and taken as input parameter to train the neural network. A comparative study on characterization have been carried out using feed-forward back propagation (FFBP) and cascade-forward back propagation (CFBP) algorithms. The results of both algorithms are evaluated with Mean Square Error (MSE) as a prediction performance measure. The average percentage error for length, depth and width are also computed. The result shows that the feed-forward back propagation network model performs better in characterizing the defects.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1877-1880
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• 2005

This paper proposed the new current feed-back amplifier for low supply voltage application. The input stage was designed to be a class-AB circuit and achieve the low supply-voltage operation down to $2V_{TH}+2V_{DS(SAT)}$. With the self-adjust bias current, the high performance can be adopted with high stability. The circuit was successfully proven by the simulation with MOSIS 0.5 ${\mu}$m MOS technology.