• Korean Journal of Adult Nursing
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• v.27 no.2
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• pp.211-222
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• 2015

Purpose: This study was conducted to test the model for sleep in community-dwelling older adults. The hypothetical model based on a senescent sleep model was constructed using the multiple influencing factors of sleep and associated adverse outcomes of changes in sleep in the older adults. Methods: Data were collected from 203 community-dwelling older adults living in Korea, and analyzed using IBM SPSS 21.0 and AMOS 21.0. Results: Increased age and multiple comorbidities were associated with decreased physical activities. Decreased physical activities were associated with smaller social networks, and smaller social networks were associated with higher level of loneliness. Multiple comorbidities, decreased physical activities, larger social networks, and higher level of loneliness were associated with maladaptive sleep hygiene. Decreased physical activities, higher level loneliness, and shorter actual sleep duration were associated with worse sleep quality. Smaller social networks and shorter actual sleep duration were associated with lower cognitive functions. Smaller social networks, higher loneliness, and worse sleep quality were associated with more severe depressive symptoms. Conclusion: These findings suggest that the sleep improvement interventions not only with physical perspectives but psychosocial ones for older adults may improve depressive symptoms as well as sleep quality.

• Korean Journal Plant Pathology
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• v.10 no.4
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• pp.284-291
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• 1994

In order to establish an appropriate spray schedule to reduce the infection, 11 kinds of chemicals were tested for their properties on the inhibition of spore germination at the surface of apple fruits and the duration of the inhibitory effect after spray of each chemical was examined from late June to early September with basically 10 day intervals. Actual control efficacy of each chemical by the 8 successive spray and the patterns of waterborne spore dispersals during that periods were also examined. Combining those results with the meteorological observation data, actual control efficacy of each chemical in the given periods could be estimated. It was revealed that folpet, Brodeaux mixture, mancozeb, oxine copper and imminoctadine-triacetate could be used at any time during the possible infection periods. Captan and dithianon could also be used except the rainy season due to the short duration of inhibitory efficacy against spore germination under heavy rain. However, the usefulness of propineb, benomyl and chlorothalonil against the apple white rot could not be demonstrated in this experiment. Thiram, even though has not been used for apple white rot, can also be used before or after the rainy season to control not only white rot but also alternaria blotch.

• Journal of Power Electronics
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• v.19 no.2
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• pp.333-343
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• 2019

Dead time and the nonideal characteristics of components all lead to phase voltage distortions. In order to eliminate the harmful effects caused by distortion, numerous methods have been proposed. The efficacy of a method mainly depends on two factors, the compensation voltage amplitude and the phase current polarity. Theoretical derivations and experiments are given to explain that both of these key factors can be deduced from the compensation time, which is defined as the error time between the ideal phase voltage duration and the actual phase voltage duration in one Pulse Width Modulation (PWM) period. Based on this regularity, a novel method for compensating phase voltage has been proposed. A simple circuit is constructed to realize the real-time feedback of the phase voltage. Utilizing the actual phase voltage, the compensation time is calculated online. Then the compensation voltage is derived. Simulation and experimental results show the feasibility and effectivity of the proposed method. They also show that the error voltage is decreased and that the waveform is improved.

• Korean Journal of Construction Engineering and Management
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• v.7 no.1 s.29
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• pp.138-147
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• 2006

Construction companies have been interested in the construction duration which importantly affects the performance and the success of the construction projects in accordance with the systemic changes such as five days per week system, introduction of construction duration reduction bidding system and post sale system nowadays. It is also very important to estimate and forecast properly the construction duration as the construction companies compete for the projects in the situation of construction market reduction and the lowest bidding system. Recognizing the importance about the construction duration, the researches about comparing and analyzing or estiamting the construction duration have been performed. However, comparing studies about the construction duraion have been limited to the apartment and office building in domestic area. Many studies about forecasting construction duration have been performed through stochastic analysis and simulations. Little research has been addressed the comparison analysis of the real construction duration about the mix-use building and officetel building which occured according to the changes of the building requirements. Therefore, the objective of this study is to compare and analyze the real construction duration and the hypothetical construction duration about the mix-use building and officetel building of the domestic companies. Moreover, we select the most competitve construction company to get the strengths and analyze the competitive advatages of the construction companies about construction duration.

• Journal of KIISE:Software and Applications
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• v.31 no.1
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• pp.20-28
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• 2004

Estimation of software project cost, effort, and duration in the early stage of software development cycle is a difficult and key problem in software engineering. Most of development effort and duration estimation models presented by regression model of simple relation function point vs. effort and effort vs. duration instead of considering developer's productivity. But different project have need for different effort according to developer's productivity if the projects are same software size. Also, different duration takes according to developer's productivity if the projects require the same effort. Therefore, models that take into account of productivity have a limited application in actual development project. This paper presents models that can be estimate the duration according to productivity in order to compensate a shortcoming of the previous models. Propose model that could presume development period by various methods based on productivity and compared models' performance. As a result of performance comparison, an estimating model of development period from software size got simple and most good result. The model gives decision-making information of development duration to project management in the early stage of software life cycle.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.26-33
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• 2009

The required level of detail in scheduling depends on the stages in the construction life-cycle. The objective of this study is to provide a Standardized Schedule Model (SSM) with an aim to facilitate the estimating of construction duration in the planning stage. The SSM modularizes work items; establishes relations between preceding and succeeding activities; and calculates approximate construction duration. The estimated duration of the SSM was compared with the detailed duration from the commercial scheduling tool using actual work activities. The difference showed to be ranged between -3.1% and +15%, which demonstrates that the SSM can be feasibly applied to the approximate estimation of construction duration.

• Computational Structural Engineering
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• v.5 no.1
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• pp.91-96
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• 1992

Earthquake resistant design is evolutionary, and, although great progress has been made since seismic design was made mandatory by building codes, it is still not completely understood. In this paper, a 10 story steel building is analyzed and its results are compared by applying two different actual ground motions to the structure. 12 sets of Loma Prieta, California, earthquake data which occurred in 1989, and recorded 7.1 on the Richter scale and 9 sets of Valparaiso, Chile, earthquake data which occurred in 1985, and recorded 7.8 on the Richter scale were scaled to zone 2B level of UBC-88. By applying earthquake ground motions which had similar Richter scale magnitude, it was found that the Chile earthquake which had long duration of ground motion affected about twice bigger than that of California earthquake which had relatively short duration of ground motion. In addition to the peak ground motion, the duration of the ground motion is a very important factor in structural design.

• Journal of ILASS-Korea
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• v.25 no.2
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• pp.45-50
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• 2020

Recently, global warming and environmental pollution are becoming more important, and fuel economy is becoming important. Each automobile company is actively developing various new technologies to increase fuel efficiency. CVVD(Continuously Variable Valve Duration) system means a device that continuously changes the rotational speed of the camshaft to change the valve duration according to the state of the engine. In this paper, VVT(Variable Valve Timing) and CVVD were applied to a single-cylinder diesel engine, and the characteristics of intake and exhaust flow rate and in-cylinder pressure characteristics were analyzed by numerical analysis. In order to analyze the effect of CVVD on the actual engine operation, the study was performed by setting the valve control and injection pressure as variables in two sections of the engine operating region. As a result, In the case of applying CVVD, the positive overlap with the exhaust valve is maintained, thus it is possible to secure the flow smoothness of air and increase the volumetric efficiency by improving the flow rate. The section 2 condition showed the highest peak pressure, but the pressure rise rate was similar to that of the VVT 20 and CVCD 20 conditions up to 40 bar due to the occurrence of ignition delay.

• KIEAE Journal
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• v.6 no.3
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• pp.35-42
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• 2006

The apartment buildings now covers more than 50% of the total residential types in Korea and the urban residential area becomes increasingly congested with newly constructed high-rise apartment buildings. Judicial precedents require, for securing the solar rights in the residential area, that the consecutive sunshine duration should be at least two hours from 9:00 to 15:00 or the accumulative sunshine duration should be at least four hours from 8:00 to 16:00 as of the winter solstice. Disputes are increasing, however, on infringed solar rights and view rights for the neighboring structures as cases occur where the requirement cannot be satisfied in congested residential areas. The sunshine duration scan be assessed by measuring it on the site of the dispute, but it is impracticable to actually measure it for every case on the winter solstice, only one day out of the whole year. At a trial, therefore, 3D computer simulation is used to calculate the sunshine duration and determine the extent of infringement for submission of the evaluation to be used as the basis of the judgment. The simulation, however, may have an error in its result up to the program characteristics and the accuracy of the input data such as the structure shape and height, the distance between structures, and the ground level. This study, therefore, used a self-developed VIEW program with Autodesk VIZ 2006 to provide a simulation method for solar access evaluation, and verified its efficacy by comparing the results with the actual measurements.

• Nutrition Research and Practice
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• v.10 no.1
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• pp.49-55
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• 2016

BACKGROUND/OBJECTIVES: The purpose of this study is to utilize an extended Theory of Planned Behavior in identifying predictors of exclusive breastfeeding intention and behavior among women in Kelantan, Malaysia. SUBJECTS/METHODS: A prospective cohort study was conducted, recruiting pregnant womenthrough two-stage cluster sampling. Their exclusive breastfeeding intention, attitude, perceived norm, perceived behavioral control and past behavior were obtained at baseline through interviewer-guided questionnaire. At one month after delivery, another interview was conducted to determine the two additional variables in the extended theory, which were their postpartum support and breastfeeding difficulty. The behavior, which was the actual duration of exclusive breastfeeding, was obtained from the second follow-up at six months. Pearson correlation and two hierarchical regression analyses were conducted. RESULTS: A total of 200 women completed the study follow-up. Their median intended exclusive breastfeeding duration was 4.0 (IQR 5) months, and the median actual duration was 1.0 (IQR 4) month. The Theory of Planned Behavior explained 51.0% of the variance in intention, with perceived behavioral control and attitude were the significant predictors. It also explained 10.0% of the variance in behavior, but the addition of postpartum support and breastfeeding difficulty increased the amount of explained variance in behavior by 6.0%. The significant predictors of exclusive breastfeeding behavior were intention, postpartum support and breastfeeding difficulty. CONCLUSION: The extended Theory of Planned Behaviorhad a good predictive ability in explaining exclusive breastfeedingintention and behavior. The women's intention to practice exclusive breastfeeding may be improved by improving their perceived behavioral control and attitude. Providing correct postpartum support and skills to handle breastfeeding difficulties after delivery will improve their exclusive breastfeeding behavior.