• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.1
• /
• pp.9-16
• /
• 2016

Since most of devices in the IEEE 802.15.4 LR-WPAN are expected to operate on batteries, they must be designed to consume energy in a very conservative way. Two energy conservation algorithms are proposed for the LR-WPAN: DDC (Dynamic Duty Cycle) and DBT (Dynamic Beacon Tracking). The DDC algorithm adjusts duty cycle dynamically depending on channel conditions. The DBT algorithm switches beacon tracking mode on and off adaptively depending on traffic conditions. Combining the two algorithms reduces energy consumption more efficiently for a wide range of input loads, while maintaining frame delivery ratio and average delay at satisfactory levels.

• KIEAE Journal
• /
• v.17 no.4
• /
• pp.83-88
• /
• 2017

Purpose: The objective of this study is to develop a predictive model for calculating the amount of cooling load for the different setback temperatures during the setback period. An artificial neural network (ANN) is applied as a predictive model. The predictive model is designed to be employed in the control algorithm, in which the amount of cooling load for the different setback temperature is compared and works as a determinant for finding the most energy-efficient optimal setback temperature. Method: Three major steps were conducted for proposing the ANN-based predictive model - i) initial model development, ii) model optimization, and iii) performance evaluation. Result:The proposed model proved its prediction accuracy with the lower coefficient of variation of the root mean square errors (CVRMSEs) of the simulated results (Mi) and the predicted results (Si) under generally accepted levels. In conclusion, the ANN model presented its applicability to the thermal control algorithm for setting up the most energy-efficient setback temperature.

• KIPS Transactions on Computer and Communication Systems
• /
• v.2 no.5
• /
• pp.199-202
• /
• 2013

In the cluster mechanism of the wireless sensor network, the network lifetime is affected by how cluster heads are selected. One of the representative clustering mechanisms, the low-energy adaptive clustering hierarchy (LEACH), selects cluster heads periodically, resulting in high energy consumption in cluster reconstruction. On the other hand, the adaptive clustering algorithm via waiting timer (ACAWT) proposes a non-periodic re-clustering mechanism that reconstructs clusters if the remaining energy level of a cluster head reaches a given threshold. In this paper, we propose a re-clustering mechanism that uses multiple remaining node energy levels and does re-clustering when the remaining energy level of a cluster head reaches one level lower. Also, in determining cluster heads, both of the number of neighbor nodes and the remaining energy level are considered so that cluster heads can be more evenly placed. From the simulations based on the Qualnet simulator, we validate that our proposed mechanism outperforms ACAWT in terms of the network lifetime.

• Journal of Energy Engineering
• /
• v.22 no.1
• /
• pp.1-7
• /
• 2013

This paper attempts to estimate the residential electricity demand function, using survey data of 521 households in Korea. As the residential electricity demand function provides us information on the pattern of consumer's electricity consumption, it can be usefully utilized in predicting the impact of policy variables such as electricity price and forecasting electricity demands. We apply least absolute deviation(LAD) estimation as a robust approach to estimating parameters. The results showed that price and income elasticities are -0.68 and 0.14 respectively, and statistically significant at the 10% levels. The price and income elasticities portray that residential electricity is price- and income-inelastic. This implies that the residential electricity is indispensable goods to human-being's life, thus the residential electricity demand would not be promptly adjusted to responding to price and/or income change.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.11 no.4
• /
• pp.1-6
• /
• 2015

In this study, energy performance of two types of food dryers which are electric heater and heat pump is studied experimentally. With drying chamber temperatures controlled at 45, 50 and $55^{\circ}C$, sliced radish is dried from an initial mass of 90 to final 7 kg. Moisture content, drying time, total power consumption, MER (moisture extraction rate, kg/h) and SMER (specific moisture extraction rate, kg/kWh) are measured and analyzed. As the drying chamber temperature is increased, drying time is shortened but energy efficiency is reduced for both types. For an electric heater dryer, the effect of chamber temperature on drying time is significant but less significant on energy efficiency. For a heat pump dryer, the dependence of chamber temperature on drying time is weak but strong on energy efficiency. Temperature levels have little effect on electric heater dryer performance but strong effect on heat pump dryer which operates on a vapor compression refrigeration cycle. The energy performance of the heat pump dryer is superior with an average SMER of 2.175 kg/kWh which is 2.22 times greater than that of the electric heater dryer with SMER of 1.224 kg/kWh.

• Journal of Community Nutrition
• /
• v.5 no.2
• /
• pp.105-111
• /
• 2003

Balanced intake of appropriate nutrients is the key to sustaining and promoting health as well as preventing and treating diseases. It is not always easy, however, to take balanced nutrition and various related factors must be taken into consideration. This report provides a summary of studies that have examined the nutrient intakes of Japanese middle-aged men and the relationship of this intake to drinking, job-related separation from families, and health practices. The alcohol consumption of Japanese middle-aged men has more than tripled in the last forty years. When nutrient intake was examined in relation to alcohol consumption, it was discovered that the maximum acceptable alcohol consumption was approximately 23 grams (about two drinks) of pure alcohol, provided the level of nutrient intake for drinkers was equal to that of non-drinkers. The alcohol energy ratio was approximately 5％. It was also discovered that middle-aged men's eating habits deteriorate when they relocate to new posts without their families and live by themselves. Compared to those living with their families, a higher proportion of those living alone have unfavorable eating habits including skipping breakfast or lunch, having a late lunch, and eating and drinking after dinner until bedtime. When Breslow's seven health practices, nutrient intake, and consumption weight by food group were examined, it was discovered that the group that had many beneficial eating and living habits consumed plenty of legume, pulses, fruit, green yellow vegetables and milk products. Their intake of vitamins and minerals was high and the results of a physical examination proved to be excellent. According to nutrition surveys conducted in Japan, China, the United Kingdom and the United States using a 24-hour recall method with common protocols and strict controls to ensure high levels of accuracy and cross-study validity, the Japanese had the highest cholesterol intake and the lowest dietary fiber intake among the four countries. Also, the alcohol energy ratio of the Japanese exceeded 8％, the highest among the four countries, while their intake of magnesium and iron was the lowest These results indicate that it is necessary to enhance nutritional education for middle-aged men and to reinforce the social environments in which they live and work in order to promote proper diet and nutrition in Japan. (J Community Nutrition 5(2) : 105-111, 2003)

• Journal of Electrical Engineering and Technology
• /
• v.10 no.3
• /
• pp.755-765
• /
• 2015

A thermostatically controlled load (TCL) can be one of the most appropriate resources for demand response (DR) in a smart grid environment. DR capability can be effectively implemented in a TCL with various intelligent control methods. However, because traditional on-off control is still a commonly used method in a TCL, it is useful to develop a method for adding DR capability to the TCL with an existing on-off controller. As a specific realization of supervisory control for implementing DR capability in the TCL, two methods are proposed - a method involving the changing of a set point and a method involving the paralleling of an identified system without delay. The proposed methods are analyzed through the simulations with an electric heater for different power consumption levels in the on-state. Considerable cost benefit can be achieved with the proposed methods when compared with the case without DR. In addition, the observations suggest that a medium power consumption level, instead of the maximum power, in the on-state should be used for consistently obtaining the cost benefit without severe temperature deviation from the specified temperature range for DR.

• Journal of the Korean Society of Food Culture
• /
• v.26 no.2
• /
• pp.101-112
• /
• 2011

The objective of this study was to examine alcohol consumption rates and the perception of drinking cultures among college students in the Wonju area. An examination of factors such as frequency of drinking, average quantity consumed, and frequency of heavy drinking suggested that the drinking rates were relatively high. Over 70% of subjects drank at least once a week, 66.2% typically drank more than 5 servings at a time, and 19.2% of males and 13.0% of females were heavy drinkers. It was revealed from an AUDIT (Alcohol Use Disorder Identification Test) assessment that 71.3% of the subjects tested had various levels of alcohol-related problems. These problems were more severe in subjects that were male, selfboarding, or overweight. Alcohol related knowledge was not high because the subjects didn't know or incorrectly recognized some contents such as blood alcohol concentration, the energy content of alcohol, and the empty caloric characteristics of alcohol. Generally male, self-boarding, and overweight persons were not critical of the undesirable characteristics associated with drinking culture. Two opinions that were generally considered to be permissible were: 'Men should be able to drink' and 'Drinking is essential for a smooth human relationship'.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2003.10a
• /
• pp.17-18
• /
• 2003

Although flounder is one of the most important marine fish for aquaculture in Korea, feeding the flounder in commercial farms depends mainly on moist pellet in which over 70% frozen fishes (e.g. frozen horse mackerel) are incorporated in its formulation. Therefore, for further expansion of flounder farming, it is essential to employ practical formulated feeds that can support reasonable growth. Development of nutritionally balanced and cost-effective feeds is dependant on the information about nutritional requirement and feed utilization of the species. Nutrient and energy source in feed are needed for the growth and maintenance of fish. Protein is probably the most important nutrient affecting fish growth and feed cost. Therefore, it is essential to determine the optimum dietary protein level for the growth of fish, both its high proportion in the feed and because it is the main factor in determining feed cost. Dietary energy level is also critical because protein source in the feed is utilized as an energy source when the feed deficient in energy is fed to fish, whereas when the feed excess in energy is fed to fish, feed consumption decreased and resulted in growth reduction due to lack of other necessary nutrients for normal growth. Improper dietary protein, energy levels and/or their ratio will lead to an increase of fish production cost and deterioration of water quality resulting from wasted feed; thus, they are important in formulating commercial feed. Dietary lipids play important roles in providing energy and essential fatty acid for normal growth and survival of fish. Although carbohydrates are not essential nutrients for carnivorous fish, these compounds play important roles as a low-cost energy source for protein sparing and also as a feed binder. Nutrition researches for flounder have identified its requirements of protein, lipid and essential fatty acid, vitamin, and minerals for normal growth. Other studies have also been carried out to investigate the utilization of the protein, lipid and carbohydrate sources. Based on these nutritional information obtained, practical feed formulations have been studied for improve aquaculture production of flounder. The results of the researches on utilization of dietary protein, lipid and carbohydrate by flounder are discussed in this review.

• Journal of Nutrition and Health
• /
• v.22 no.1
• /
• pp.1-8
• /
• 1989

The study was attempted to observe effects of voluntary exercise on energy expenditure and on storage of excessive energy into body fat in adult mice. Mice, body weight 25-30g, were divided into two groups, exercise and sedentary group. Voluntary exercize by running wheel was allowed for former group but not for the mice of the latter group which were restricted by limiting space allowance 13.5$\times$11.5$\times$15.0cm per mouse. During a period of 4 weeks of feeding trial, they were fed ad libitum starch-casein based diet added with $^3\textrm{H}$-glucose (D-[1-$^3\textrm{H}$(N)]-glucose) at a level of 20 nCi per g of diet. Measurements were made to study hematology, lipase activity in epididymal adipose tissue, total contents of body waste and fat, and radiactivity of $^3\textrm{H}$-glucose incoporated into body fat. Dietary intake, body weight gain and amount of voluntary physical activities were also measured. The results obtained ard summarized as follows; 1) Amount of metabolizable energy intake, body weight gain and body fat were not statistically different between the two group. However, mice of the exercise group tended to show lower body weight gain body fat contants, but higher energy expenditure than those of the sedentary group. 2) Radioactivity of $^3\textrm{H}$-glucose incoporated into body fat appeared lower for exercise group expressd on a whole body fat basis. The activity was, however, higher for exercise group when expressed based on per g of fat compared to that of sedentary group. 3) Exercise group showed also higher activity of lipase in epididymal adipose tissue than the other group. 4) Mice whose physical activities were restricted appeared to have lower levels of hemoglobin and hematocrit values than of the exercise group. These results seem to support the theory that turn-over rate of body fat is activated by exercise and to suggest that consumed energy is to be converted primarily into body fat before its use as energy source by oxidation even during a period of continuous energy expenditure by exercise.