간척지에서 옥수수 나방류 해충 3종의 발생소장

이휘종,최원영,김상열,서종호,황정동,오성환,정진교,김주일,구현나,김길하 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.2

Occurrence of three troublesome lepidopterous pests, Ostrinia furnacalis, Helicoverpa armigera and Pseudaletia separata in corn cultivation of the reclaimed land were recorded using sex pheromone traps from 2012 to 2014. In case of O. furnacalis adult, two generations were observed in a year and its occurrence pattern was very regular. The 1st generation showed the highest occurrence in late May-early June and the 2nd generation was in late July-early August. On the other hand, H. armigera occurred at least three times a year but its occurrence was somewhat irregular. H. armigera adult showed the highest occurrence in mid May, late June, early August, respectively in 2012 but their occurrence patterns of the 2nd and 3rd generations were varied in 2013 and 2014. In case of P. separata, a few number of adult were captured during the survey period, indicating few number of P. separata migrated from China. Based on the control effect of O. furnacalis by Etofenprox and Carbofuranin 2012, June 26 treatment showed the highest control rate with 96.8% for Etofenprox, 85.8% for Carbofuran, respectively. Late treatment at June 19 and June 26 significantly decreased the control rate of O. furnacalis and June 26 treatment showed the lowest control rate of 1.9% for Etofenprox. 18.1% for Carbofuran, respectively.

주요우울증이 근로자의 생산성에 미치는 영향 : WHO-HPQ(Health and Work Performance Questionnaire)를 이용한 예비연구

김원,황태연,함병주,이준석,최병휘,김세주,서용진,강은호,우종민 大韓神經精神醫學會 2007 신경정신의학 Vol.46 No.6

Objectives : Major depressive disorder (MDD) causes patients' distress and makes socioeconomic burden, both directly and indirectly. We used the concept of lost productive time (LPT) to estimate the indirect costs and calculated both absenteeism and presenteeism among workers with MDD. Mcthods : Depression group was recruited from workers visiting psychiatric outpatient clinic who had MDD without major physical or mental disorders (N= 106). Age and sex matched healthy control group was also recruited through advertisement (M=100). All participants completed a interview using WHO Health and Work Performance Questionnaire (HPQ), Job Stress Measurement Scale for Korean Employees, and Hamilton Rating Scale for Depression. Statistical analysis was performed with independent t-test or χ² test as characteristics of values (p=0.05). Results : The number of absence (0.94-day/month vs. 0.10-day/month, P=0.015) andthe numberofearly leaving (2.56-day/month vs. 0.24-day/month, P<0.001) were significantly higher in the depression group. Depression group evaluated their Perfor-mance level much lower than controls with significant value (5.16 vs. 7.62, P<0.001). In addition, depression group estimated their performance level during the last 4 weeks lower compared to the level of past 1-year (5.16 vs 6.63, P<0.001). The estimated costs of absenteeism in depression group were higher than controls by 2,520,000 Korean Won per year, and those of presenteeism were also higher by 4,880,000 Korean Won per year. The total costs of LPT in depression group were higher than controls by 7,400,000 Korean Won, which corresponds to 26% ofmean annual salary. In addition, the level of occupational stress, such as high demand and interpersonal conflict, was higher in the depression group. Conclusion : Major depressive disorder costs substantial productivity loss to workers and their company. Presenteeism imposes more time cost than absenteeism. Effectiveness trials are needed to devise cost-effective programs for the early detection and treatment of depression at the workplace.

DYNAMIC LOAD ANALYSIS AND DESIGN METHODOLOGY OF LCD TRANSFER ROBOT

Jong Hwi Seo,임홍재,Jae Chul Hwang,Yong Won Choi,Dong Il Kim 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.4

The objective of the present study is to develop a design methodology for the large scale heavy duty robot to meet the design requirements of vibration and stress levels in structural components resulting from exposure of system modules to LCD (Liquid Crystal Display) processing environments. Vibrations of the component structures significantly influence the motion accuracy and fatigue damage. To analyze and design a heavy duty robot for LCD transfer, FE and multi-body dynamic simulation techniques have been used. The links of a robot are modeled as flexible bodies using modal coordinates. Nonlinear mechanical properties such as friction, compliance of reducers and bearings were considered in the flexible multi-body dynamics model. Various design proposals are investigated to improve structural design performances by using the dynamic simulation model. Design sensitivity analyses with respect to vibration and stresses are carried out to search an optimal design. An example of an 8G (8th-Generation) LTR (LCD Transfer Robot) is illustrated to demonstrate the proposed methodology. Finally, the results are verified by real experiments including vibration testing.

Nonlinear Dynamic Analysis of a Large Deformable Beam Using Absolute Nodal Coordinates

Jong-Hwi Seo,Il-Ho Jung,Tae-Won Park 한국정밀공학회 2004 International Journal of Precision Engineering and Vol.5 No.4

A very flexible beam can be used to model various types of continuous mechanical parts such as cables and wires. In this paper, the dynamic properties of a very flexible beam, included in a multibody system, are analyzed using absolute nodal coordinates formulation, which is based on finite element procedures, and the general continuum mechanics theory to represent the elastic forces. In order to consider the dynamic interaction between a continuous large deformable beam and a rigid multibody system, a combined system equations of motion is derived by adopting absolute nodal coordinates and rigid body coordinates. Using the derived system equation, a computation method for the dynamic stress during flexible multibody simulation is presented based on Euler-Bernoulli beam theory, and its reliability is verified by a commercial program NASTRAN. This method is signinficant in that the structural and multibody dynamics models can be unified into one numerical system. In addition, to analyze a multibody system including a very flexible beam, formulations for the sliding joint between a very deformable beam and a rigid body are derived using a non￢generalized coordinate, which has no inertia or forces associated with it. In particular, a very flexible catenary cable on which a multi body system moves along its length is presented as a numerical example.

Adaptability of Late-planted Corn for Silage or Grain Production to Double Cropping with Winter Barley

Jong-Ho Seo, Jung-Kyung Moon, Ja-Hwan Gu, Gun-Ho Jung, Min-Jung Seo, Seong-Hyu Shin,Dae-Wook Kim, Chung-Dong Hwang, Hwi-Jong Lee, Sung-Hwan Oh,Weon-Young Choi, and Young-Up Kwon 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.1

Introduction of double cropping of winter cereals-summer corn is important for increasing grain self-sufficiency in South Korea. Adaptability for cropping seasons, and silage and grain yields of double cropping corn planted in early- and late-June to winter barley were compared with single cropping corn planted normally in late April for 2008 and 2009 in central part of Korea. Physiological maturity of corn planted in June was delayed to late September or mid October while that of single cropping corn planted in April was delayed to late August. There was not much difference in total GDD among planting times. Stover DM of corn was 30% less than that of single cropping corn, but reduction of ear DM or grain yields by later planting due to double cropping was 4% less. Yields of double-cropped corn, particularly in ear DM or grain yield increased as planting density increased to 7.78 × 104 plants ha-1. It is thought that the double cropping of winter barley-corn for silage production could be accepted easily because of better weather condition for corn harvest, higher annual total silage yield and enough time for seedbed preparation for barley. Double cropping with barley silage for corn grain could be practiced without reduction of corn grain. But cropping season of barley grain - corn grain was short because of overlapping between corn maturity and annual barley seeding in mid-October.

여유구속을 갖는 유연체 기계시스템의 동역학 해석

서종휘(Jong-Hwi Seo),박태원(Tae-Won Park),채장수(Jang-Soo Chae),서현석(Hyun-Seok Seo) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.4

Many mechanical systems are over-constrained if only rigid bodies are used to model the system. One<br/> example of such system is a satellite system with solar panels. To avoid this over-constrained problem, solar<br/> panels can be modeled as flexible bodies. The CMS(Component Mode Synthesis) method is widely used to<br/> analyze the flexible multi-body system because it can considerably approximate the deformation of the<br/> flexible bodies using small number of well-selected mode. However, it is very difficult to decide the boundary<br/> condition and the selection of modes. In this paper, the methods for mode synthesis and setting the boundary<br/> condition are presented to analyze the flexible multi-body system with over-constraints. Finally, the reliability<br/> of proposed method is verified by solar panel's deployment test.

Glass Panel 연마설비의 동역학 특성 해석에 관한 연구

서종휘(Jong-Hwi Seo),장현수(Hyun-Soo Jang),박태건(Tae-Gun Park),최장수(Jang-Soo Choi),박태원(Tae- Won Park) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5

In this paper, A dynamic analysis model of lapping machine which is grinding a glass panel is proposed. This analysis model is available for predicting the dynamic performance to develope the new lapping machine. Analysis results are aplied to predict the quality of glass panel after manufacturing. Finally, we also developed the only design program for a user who is lapping engineer in spot.

절대절점좌표를 이용한 탄성 다물체동역학 해석에서의 동응력 이력 계산에 관한 연구

서종휘(Jong-Hwi Seo),정일호(Il-Ho Jung),박태원(Tae-Won Park) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.5

Recently, the finite element absolute nodal coordinate formulation (ANCF) was developed for the large deformation analysis of flexible bodies in multi-body dynamics. This formulation is based on the finite element procedures and the general continuum mechanics theory to represent the elastic forces. In this paper, a computation method of dynamic stress in flexible multi-body dynamics using absolute nodal coordinate formulation is proposed. Numerical examples, based on an Euler-Bernoulli beam theory, are shown to verify the efficiency of the proposed method. This method can be applied for predicting the fatigue life of a mechanical system. Moreover, this study demonstrates that structural and multi-body dynamic models can be unified in one numerical system.

유한요소법을 이용한 냉각홴의 진동 및 간섭에 관한 연구

서종휘(Seo, Jong-Hwi),송하종(Song, Ha-Jong),박태원(Park, Tae-Won),김주용(Kim, Joo-Yong),정일호(Jung, Il-Ho) 한국소음진동공학회 2004 한국소음진동공학회 논문집 Vol.14 No.9

A CFA(cooling fan assembly) is composed of a fan, motor and shroud, which is at the back of the automotive radiator. By forcing the wind to pass, the CFA controls the cooling performance of the radiator. The noise and vibration of the CFA may be primarily due to the resonance between the CFA and engine. The Interference among the fan, shroud and radiator by deformation is considered when the CFA is designed. In this paper, in order to analyze the structural vibration of the CFA for automobiles, a finite element model of the CFA is established by using a commercial FEM code. After the finite element modeling, the natural frequencies and the mode shapes are obtained from the FE analysis. The natural frequencies are obtained from the vibration test as well. Then, the results of the vibration test are compared with those of the FE analysis. The natural frequencies obtained by experiment have a great similarity to the results from FE model. We have confirmed the validity of the FE model and verify the structural safety for the resonance. The stress and displacements are obtained from FE analysis. We have confirmed the safety for the interference and failure.

고속전철 집전시스템의 동역학 해석에 관한 연구

서종휘(Jong-Hwi Seo),정일호(Il-Ho Jung),박태원(Tae-Won Park),목진용(Jin-Yong Mok),김영국(Young-Guk Kim),김석원(Seok-Won Kim) Korean Society for Precision Engineering 2005 한국정밀공학회지 Vol.22 No.1

The dynamic properties between catenary and pantograph of high-speed train are very important factors to affect the stable electric power supply. So as to design the reliable current collection system, a multibody simulation model is needed. In this paper, the dynamic analysis method for a pantograph-catenary cable system of high-speed train is presented. The very deformable motion of a catenary cable is demonstrated using nonlinear continuous beam theory, which is based on an absolute nodal coordinate formulation, and the pantograph is modeled as a rigid multibody. The proposed method might be very efficient, because this method can present the nonlinear properties of a flexible catenary cable and set a various boundary conditions.