• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.2
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• pp.166-173
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• 2006

This study investigates a heavy duty diesel engine with swept vol. 12.6L, 4cycle-OHC type to verify the effects of the performance and exhaust gas emission according to the variable specifications of both swirl ratio and flow coefficient in inlet port, combustion bowl and fuel injection system. To meet the high BMEP and stringent exhaust emission standard, a turbocharger with wastegate and an intercooler were installed in the engine. Helical port, major design parameters for combustion chamber and electronic fuel injection pump with 1,000bar were reviewed and applied. Confirmation tests were also performed to meet the target value, $NO_x$ 5.0g/kWh and PM 0.1g/kWh of Euro3 exhaust emission legislation. The results of this study show that not only is it effective to use a relatively bigger bowl size for controlling rapid burning condition due to the decreased in-bowl swirl, but also to use a concave cam with double injection rates to decrease $NO_x$.

• Journal of Preventive Medicine and Public Health
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• v.40 no.6
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• pp.454-460
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• 2007

Objectives : Obesity is currently an epidemic in Korea, and sleep duration is thought to be one of the risk factors for obesity. The objective of this study was to test the hypothesis that short sleep duration is associated with obesity in Korean adults. Methods : The data from the 2001 Korean National Health and Nutrition Survey were used, and 6,174 subjects aged $18{\sim}80$ years were included in the analysis. Sleep duration was measured using information obtained from self-reported questionnaires. Obesity, the main outcome variable, was measured according to body mass index. Multiple regression modeling was used to adjust for potential confounding variables. Results : The study results revealed a negative association between sleep duration and body mass index among Korean adults. These associations persisted after controlling for the potential confounding variables. Conclusions : These findings support the hypothesis that sleep duration is associated with obesity in Korean adults. In addition, these observations support earlier experimental sleep studies and provide a basis for future studies on weight control intervention by increasing the amount of sleep.

• Research in Plant Disease
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• v.8 no.1
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• pp.50-54
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• 2002

A total of 55 Colletotrichum isolates from strawberry plants with anthracnose symptoms(crown rot) were inhibited in mycelial growth on potato-dextrose agar(PDA) amended with fungicides in variable degrees depending on the chemicals used, especially showing no growth on PDA with 1 mg/m/tricyclazole. However, in the detached leaf test by treating chemicals before or after inoculation of Colletotrichum sp., tricyclazole was little effective in controlling symptom development; instead azoxystrobin, which had low in vitro inhibition of mycelial growth, inhibited strongly the symptom development. Some chemicals were tested for the control of strawberry crown rot in greenhouse using three methods, sprays soil drenching and plant dipping. No or little control effect were made by chemical spray and soil drenching, but plant dipping in chemical solution, especially azoxystrobin: reduced crown rot development by about 50% in the greenhouse suggesting that the azoxystrobin treatment may be an effective control method of the crown rot of strawberry. No differences in the control efficacy were noted according to the dipping time and chemical concentration of azoxystrobin not less than 10 min and 250 mg/m/, respectively.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.488-493
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• 2009

The very big springback of advanced high strength steel(AHSS) sheets invokes undesired shape defects, which can be generally eliminated by die correction or process parameter control. The springback reduction by controlling the forming process parameters is easy for the application, but limited for the bulky achievement. In this study, the effective die correction method, which obtains the modification of tool shape from the relationship between die design variable and springback, is introduced and is applied to the TWB tool of automotive side rail to show the validity and usefulness. Among the die correction trials repeatedly performed, the first trial is carried out by correcting the tool shape to the opposite direction to the springbacks of several tool sections. Next trials are done by extrapolating the springbacks of among the original tool uncorrected and the tools corrected negative amounts of the springback and by finding tool shapes without springbacks. After the angle of side wall and radius of curvature of horizontal bottom floor are chosen as design variables in the tool design of side rail, the tool shape is corrected 3 times. The accuracy of final shape within the assembly limit of 1mm and the springback reduction of 75.8% compared to the uncorrected tool are achieved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.126-132
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• 2006

In this paper, we aim to control the sound and vibration spatially, so that a desired physical variable is enhanced within a zone we select. This is somewhat analogous to have manipulators that can draw wave shape in any place we want. Brightness and contrast control have shown that such a manipulation is possible by controlling multiple sources[J.-W. Choi and Y.-H. Kim, J. Acoust. Soc. Am. 111(4), 2002]. In particular, the acoustic brightness control seeks a way to increase loudness of sound over a chosen area, and the contrast control aims to enhance loudness difference between two neighboring regions. This enables us to manipulate spatial distribution of sound by making two different kinds of zone ? the bright and dark zone- at the same time. The primary focus of this study is to unit the theoretical formulation of the brightness and contrast control and to find a link between these methods, as well as its relation to other conventional techniques. It is also shown that we can generate various shape of wave field by transforming the domain we consider.

• The Korean Journal of Pain
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• v.1 no.1
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• pp.28-33
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• 1988

Neurolysis of the celiac plexus has been performed to relieve intractable pain caused by carcinoma of the pancreas, liver, gall bladder or stomach. It is also occasionally effective in controlling the pain of chronic pancreatitis. In practice, however celiac plexus block is not a simple procedure to the beginner. The results and complications are variable. In order to correctly inject neurolytic agents into or near the celiac plexus and to reduce the time consumed to perform celiac plexus block, we used CT scanner for 7 cases of alcohol celiac plexus block. The effects will be described. The purpose of this article is to improve the technical aspect of celiac plexus block to the beginner.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.8
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• pp.233-247
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• 1999

Traffic accidents are normally caused by late or faulty judgements due to the driver's inaccurate estimation of the distance, velocity, and acceleration from the surrounding vehicles as well as his carelessness or inattention. Thus, the development of collision avoidance systems is motivated by their great potential for increased vehicle safety. A typical collision avoidance system consists of the forward-looking sensor, the criteria for activation of collision warming and avoidance, the collision avoidance maneuvers, and the user interface. This thesis is concerned with the development of a collision warning algorithm in which the driver is warned of approaching collision with the visual and/or the audible signals . The warning algorithm based on fuzzy logic is presented here based on new warning criteria. It has been newly derived from the conventional warning equation by adding a new input variable of the required deceleration to avoid collision. The algorithm is also able to adapt to the individual driver's taste along with the different road conditions by externally controlling the warning intensity. Finally , the proposed algorithm has been validated using computer simulation.

• Journal of Power System Engineering
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• v.17 no.5
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• pp.64-68
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• 2013

One of the water management goals in PEM fuel cell is to avoid flooding and drying in the membrane, therefore the air humidification process is required. In order to increase water removal out of the membrane, the water management system may require the dehumidification process and it also requires a large space for application, moreover the process time is slow. In conformity with this fact, this present study proposes an advanced dynamic fuel cell water management which can be an intermittent optimization control using air flow rate instead of the air humidity as an variable in the optimization process. The results of this study have shown that the membrane flooding and drying can be avoided after being assisted by air velocity controlling method.

• The Research Journal of the Costume Culture
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• v.18 no.5
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• pp.842-856
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• 2010

The relationships between fashion and architecture have been interactive. Since the fashion has had the role to decide the structure type of urban environment, it is becoming the new sign of space boundary. This study searches the social and cultural characteristics of Nomadism and the relationships among all kinds of changing objects. After then, the module system characteristics are meditated by analyzing the composition method of module system in architecture. Moreover, the study examines the aesthetic values in the fashion and body architecture from artistic aspect. Based on the above discussion, the followings are the characteristics of body architecture as the social structures expressed in modern fashion. The liquidity is the fluid form of dynamic structures. It shows the extended space form which produces the continuity. The transformation is the variable structure by module system and it forms the diversified structural combination. The movement combines the controlling function to be able to regulate and move freely the body related objects. The convergence is the text combination interpenetrated mutually in enlarged space. Through this, the non-linear continuity and the access of the individual factors are shown.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.97-106
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• 2018

Improved load-following capability is one of the most important technical tasks of a pressurized water reactor. Controlling the nuclear reactor core during load-following operation leads to some difficulties. These difficulties mainly arise from nuclear reactor core limitations in local power peaking: the core is subjected to sharp and large variation of local power density during transients. Axial offset (AO) is the parameter usually used to represent the core power peaking. One of the important local power peaking components in nuclear reactors is axial power peaking, which continuously changes. The main challenge of nuclear reactor control during load-following operation is to maintain the AO within acceptable limits, at a certain reference target value. This article proposes a new robust approach to AO control of pressurized water reactors during load-following operation. This method uses robust feedback-linearization control based on the multipoint kinetics reactor model (neutronic and thermal-hydraulic). In this model, the reactor core is divided into four nodes along the reactor axis. Simulation results show that this method improves the reactor load-following capability in the presence of parameter uncertainty and disturbances and can use optimum control rod groups to maneuver with variable overlapping.