• 한국소음진동공학회논문집
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• 제23권7호
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• pp.654-661
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• 2013

The dynamic characteristics of a free-piston stirling engine(FPSE) with regard to the working frequency is investigated from theoretical and experimental studies. The FPSE is modeled as a two degree-of-freedom linear vibration system. A theoretical expression on the working frequency is derived from the instability condition for self-excitation based on the linear vibration model. A ${\gamma}$-type free-piston stirling engine is fabricated for experimental studies, and its working frequency is measured on various heater temperatures. Comparisons between the theoretical and experimental results reveal that the working frequency of the test FPSE depends on both the temperature of the compression space and the temperature difference between the expansion and compression spaces.

• 한국산학기술학회논문지
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• 제10권3호
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• pp.567-571
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• 2009

본 연구는 단어 재인에서 작업 기억의 역할을 규명하기 위하여 진행되었다. 단어 재인에서의 작업 기억 역할 규명을 위하여 단어 빈도와 직업 기억 부담을 조절한 명명 과제 실험을 실시하였다. 실험 결과 단어 빈도는 작업 기억 부담에 영향을 받는 것으로 분석되었다. 작업 기억의 부담은 고빈도 단어 재인에서보다 저빈도 단어 재인에서 더 높은 영향을 미쳤다. 이러한 결과는 작업 기억이 저빈도 단어 재인에서 더 많은 영향을 갖음을 시사하는 것이다.

• Human Ecology Research
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• 제56권4호
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• pp.361-375
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• 2018

This study recognizes the changes of the father's role and the importance of family mealtimes as well as examines the individual, family and social contexts surrounding the father's family mealtime. This study analyzed the trend of the father's family mealtime frequency and factors affecting them in order to explore the current conditions of their father's work and family balance through family mealtimes. Data from 492 fathers who have school aged children were collected through an online survey. The overall trend of the frequency of father's family meals showed an average of 2.4 breakfasts and an average of 3.2 dinners per week. The frequency of the father's family meals showed statistically significant differences according to the father's age, children's school age, dual income, weekly working hours, working flexibility, leaving on-time and the priority of work and family. The analysis of hierarchical linear regressions was conducted to determine factors affecting the frequency of father's family mealtime to show that the frequency of father's family mealtime was best explained by father's working conditions and perception variables. Working conditions such as working hours, leaving work on time, working flexibility were significant variables in regards to the father's family mealtime frequency. The father's perception towards parental efficacy, wife's support, and work-family priority were significant factors in regards to the father's family mealtime frequency. This study is meaningful in that it provides basic data on policy making for the compatibility of the father's work and family.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1651-1656
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• 2005

This paper describes a natural frequency analysis conducted to find out a suitable working area for a spring-manipulator system generating a large vibrating force with mechanical resonance. Large force generation is one of the functions that we hope for a robot. For example, a weeding robot is required to generate a large force, because some weeds have roots spreading deeply and tightly. The spring-manipulator system has a spring element as an end-effector, so it can be in a state of resonance with the elasticity of the spring element and the inertial characteristics of the manipulator. A force generation method utilizing the mechanical resonance has potential to produce a large force that cannot be realized by a static method. A method for calculating a natural frequency of a spring-manipulator system with the generalized inertia tensor is proposed. Then the suitable working area for the spring-manipulator system is identified based on a natural frequency analysis. If a spring-manipulator system operates in the suitable working area, it can sustain mechanical resonance and generate a large vibrating force. Moreover, it is shown that adding a mass at the tip of the manipulator expands the suitable working area.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.579-587
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• 2008

Promotion of the line no.2 in Seoul Metro was changing from the existing signaling facilities for ATS(Automatic Train Stop) vehicles to the up-to-date signaling facilities for ATO(Automatic Train Operation). But, in consequence of conducting a trial run after being equipped with the ATO signaling facilities, the matter related to mix-operation with the existing ATS signaling facilities appeared. The operation of the existing ATS signaling system in combination with the ATO signaling system has made improper working related to frequency recognition of the ATS On-board Computerized Equipment. This obstructs operation of a working ATS vehicle. That is, as barring operation of an ATS vehicle that should proceed, it may make the proceeding ATS vehicle stop suddenly and after all, it will cause safety concerns. In this paper, we designed a wayside track occupancy detector that previously prevents improper working related to frequency recognition of the ATS On-board Computerized Equipment by gripping classification and working processes of operating trains throughout transmission of local signaling information from the existing facilities, which does not need to change or replace the existing signaling facilities. Furthermore, we described general characteristics of the wayside track occupancy detector and modeled the IFC(InterFace Contrivance) device and the logical circuit recognizing signal information. Then, we made an application program of PLC(programmable Logic Computer) based on the stated model. We, in relation to data transfer method, used the frame in TCP/IP transfer mode as the standard, and we demonstrated that ATO transmission frequency is intercepted.

• 농업과학연구
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• 제48권1호
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• pp.83-93
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• 2021

The 52-hour workweek policy in Korea is a system that limits the maximum working hours per week to 52 hours including holiday work, which has been treated separately from overtime work during a week. Although this policy is designed to improve the quality of life and create jobs, it may also reduce the income of some workers. In general, it can be assumed that reduced working hours increase consumption at home. This study analyzed the effect of the 52-hour work policy on meat consumption patterns with the ordered logit model. Major factors considered in this study include working hours, income, and consumption frequency. It distinguished domestic and workplace consumption. The results show that the policy has had an impact on meat consumption patterns both at home and at work. If there is no change in income and only the working hours decrease, meat consumption in households increases. On the other hand, if both income and working hours decrease, household meat consumption decreases. Moreover, reduced working hours decrease the frequency of office happy hour and meat consumption in the workplace. However, the 52-hour workweek policy applies only to workers working more than 52 hours per week; thus, it is difficult to determine the overall effect of the policy on national meat consumption patterns.

• Journal of Biosystems Engineering
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• 제25권5호
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• pp.351-358
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• 2000

This study was conducted to develop a speed control system of a DC motor which drove a barley seeder mounted on a combine harvester. Barley seeder mounted on a combine has been known to reduce labor and cost of barley cultivation. However, development of the seeder has been unsuccessful because the combine, a dedicated rice and barley harvester has not enough space and proper power take-off for barley seeder. To develop a barley seeder, small powered motor speed controller was required. A proximity sensor for detecting working speed of the combine and a programmable one board microprocessor was used to develope a control system. Motor parameters and motor constant, relationship between seeding rate, motor speed, groove volumes of a tested roller, torque were measured. The proximity sensor sent a frequency signal to the microprocessor. In laboratory experiments, the excitation voltage of the motor was shown not to be proportional to the size of pulse width (duty ratio). A table transforming frequency signal, that represented for working speed to proper pulse width was developed from seeding rate experiments. However, seeding rate at low frequency signal was not proportional to the working speed. Seeding rate control proportional to the frequency signal was achieved by shifting of the frequency signal.

• 대한지역사회영양학회지
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• 제14권6호
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• pp.789-797
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• 2009

In order to investigate the effects of frequent eating-out and breakfast skipping of working men on body mass index and nutrients intake status, working male adults aged 20 or over were selected (n = 1883) from the data of 2001 Korea national health and nutrition survey. The subjects were divided into 4 groups according to the eating-out frequency(high: once or more daily, low: less than once daily) and breakfast eating or not. Four groups were high eating-out with breakfast eating (n = 609), high eating-out with breakfast skipping (n = 192), low eating-out with breakfast eating (n = 877), and low eating-out with breakfast skipping (n = 205). High eating-out group showed higher body mass index (BMI) than low eating-out group, but the difference of BMI was disappeared when adjusted with age, residence region and family income. However high eating-out group in case of breakfast eating, compared with the low eating-out, showed higher intakes or densities of energy, fat, fat-energy% and higher ratio of energy-fat overintake, and also showed higher mean nutritional adequacy ratio and lower ratio of nutrients intake deficiency. Calcium, iron, vitamin A and C intakes were not affected by eating-out frequency, but were lowered by breakfast skipping. Breakfast skipping also decreased intake frequency of unprocessed cereals and increased those of ramyon and carbonated and alcoholic beverages. From the results frequent eating-out with breakfast eating caused increased intakes of energy and fat, but did not cause BMI increase. Breakfast skipping, but not eating-out, had negative influences on mineral and vitamin intakes. Accordingly good eating-out as well as breakfast eating should be exceedingly emphasized at nutrition education for the working males.

• 대한가정학회지
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• 제33권3호
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• pp.85-99
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• 1995

The major purpose of this research was to investigate the causal relationships among working wives' work-family conflict, socialization of housework, and home management satisfaction. the double ABCX model of family stress and adaptation provided the theoretical framework for this study. the data were recruited from working wives who had more than one pre-school child. The respondents were asked to complete the self-administered questionnaires, and the responses of 536 working wives were used for the final analysis. basically Cronbach's α to the reliability of major variables, frequencies, percentages, means, standard deviation, pearson's correlation coefficients, and LISREL 7 program were performed to test the research model. The results of this study can be summarized as follows : 1. The frequency of work-family conflict was affected by the flexibility of work time and wives' income. 2. The severity of wok-family conflict was directly influenced by the frequency of the conflict, the flexibility of work-time, and wives' education level. 3. The variables influencing the degree of socialization of housework were found to be the frequency and the severity of work-family conflict, wives' education, and the degree of husband's participation in housework. 4. The higher degree of home management satisfaction was associated with the higher level of family member's health status, the greater degree of the flexibility of work-time, and the greater degree of husband's participation in household labor.

• 한국산학기술학회논문지
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• 제11권8호
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• pp.2906-2916
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• 2010

목적 : 본 연구는 수술실 근무자들을 대상으로 작업 관련성 근골격계 부담정도와 통증에 대한 상태를 파악 하고자 실시하였다. 방법: 수술실 근무자 73명을 대상으로 설문조사와 동영상 촬영을 통하여 수술실 근무자의 작업 평가를 REBA 이용하여 인간공학적 작업분석을 실시하였다. 결과: REBA로 측정한 수술실 근로자들의 근골격계 부담정도와 근골격계 통증 정도는 상당히 높은 상태였으며 이것은 조치수준 2에 해당되며 '대상자에게 어떠한 조치가 필요하다'는 것을 의미한다. 또한 대상자 대부분이 주 3~4회 통증을 경험하고, 다리, 목, 어깨에서 심한 통증을 경험하는 것으로 조사되었다. 대상자의 일반적 특성과 통증간의 유의한 결과를 나타내는 변수로는 성별, 연령, 결혼상태, 체중, 과거직장 경험, 하루 평균 근무시간, 근무형태, 근무부서에서 유의한 관계가 있었다. 결론: 수술실 근로자는 작업과 관련하여 높은 근골격계 부담과 심한 근골격계 통증을 경험하고 있으며, 이로 인해 근골격계 질환의 가능성이 높은 것으로 나타났다.