• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.11 no.2
• /
• pp.244-249
• /
• 1999

This study is to examine the emission rate of $CO_2$gas as the environmental load in office buildings. After the investigation of monthly consumption of each energy source(electricity and natural gas), it is analyzed that the $CO_2$emission rate of 34 office buildings surveyed is 22.4kg-$c/m^2$.year, which consists of 17.5kg-$c/m^2$.year by consuming electricity, and 4.9kg-$c/m^2$.year by consuming natural gas. And the $CO_2$emission rate of each load in those buildings consists of 68% emitted by general electricity, 16% by cooling load and 16% by heating load. It is also proposed that the $CO_2$emission rate of cooling and heating load is profoundly pertinent to the variation of outdoor temperature.

• Journal of Industrial Technology
• /
• v.25 no.B
• /
• pp.211-220
• /
• 2005

The wireless sensor network consists of a number of sensor nodes which have physical constraints. Each sensor node senses surrounding environments and sends the sensed information to Sink. The inherent vulnerability in security of the sensor nodes has promoted the needs for the lightweight security protocol. In this paper, we propose a non-hierarchical sensor network and a security protocol that is suitable for monitoring the man-made objects such as bridges. Furthermore, we present the efficient way of setting the routing path by storing IDs, MAC(message authentication code) and the location information of the nodes, and taking advantage of the two node states, Sleep and Awake. This also will result in the reduced energy consuming rate.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.3
• /
• pp.119-124
• /
• 2006

This paper deals with energy-saving effort in the hydraulic power steering system. Commonly, the hydraulic power steering systems are used for passenger cars and the reduction of pumping loss under non-steering condition is important to improve fuel economy. Experiments and simulations are performed simultaneously to examine the main factors to reduce the pumping loss-pressure loss and flow rate of the power steering systems. Fuel economy effect of the optimal design of power steering system is verified by vehicle test - more than 1% fuel consuming reduction is attained.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.19 no.5
• /
• pp.125-133
• /
• 2011

The wear of rubber track being in contact with the road surface is an important subject because it decreases the traction performance and the operating efficiency of tracked vehicle. For the above reasons, many attempts have been made to quantitatively calculate the rubber track. However, it depends on the experimental methods which are highly time- and cost-consuming. Therefore, the numerical simulation approach is highly desirable, but it needs to model the complex geometry and the material behavior in details as well as the interaction with the road surface. In this study, the rubber track and its material behavior are elaborately modeled since these factors are very important in the prediction of the wear rate of the rubber track. Accordingly to the studies on the rubber wear by previous investigations, it has been found that the wear is greatly influenced by the frictional energy. The frictional energy of rubber track is computed by utilizing the 3D finite element analysis of the rubber track, and the wear rate is evaluated making use of the frictional energy and a wear model.

• Journal of the Korean Dietetic Association
• /
• v.15 no.4
• /
• pp.397-404
• /
• 2009

In this study, we examined food intake, sodium intake, and satiety rate for different methods of consuming soup. Healthy young women (n=50) participated in this study. The subjects ate cooked rice and soup using a method that they preferred and then they were assigned into separate intake groups based on how they consumed their rice and soup. One group consisted of women that ate their soup and cooked rice separately (separate intake group, n=30). The second group consisted of the women who mixed the rice and the soup prior to consumption (mixed intake group, n=20). The mixed intake group consumed significantly more food (p<0.001) and sodium (p<0.05) than the separate intake group. Because of the high water content and ease of swallowing for the mixed intake method, the eating rate of the mixed intake group (42.5 g/min) was significantly higher than that of the separate intake group (28.8 g/min) (p<0.01). However, despite consuming 79.5 g more food at lunch, the rates of satiety were not significantly different before and after eating between the mixed intake and separate intake group. Therefore, eating rate, consumption norms and concept of "clean one's bowl" may influence food intake and sodium intake. Although more studies are needed, these data suggest eating cooked rice and soup separately may help to control obesity and hypertension.

• Journal of information and communication convergence engineering
• /
• v.6 no.2
• /
• pp.117-121
• /
• 2008

In ad hoc network, the scarce energy management of the mobile devices has become a critical issue in order to extend the network lifetime. Therefore, the energy consumption is important in the routing design, otherwise cluster schemes are efficient in energy conserving. For the above reasons, an Energy conserving Context aware Clustering algorithm (ECC) is proposed to establish the network clustering structure, and a routing algorithm is introduced to choose the Optimal Energy Routing Protocol (OERP) path in this paper. Because in ad hoc network, the topology, nodes residual energy and energy consuming rate are dynamic changing. The network system should react continuously and rapidly to the changing conditions, and make corresponding action according different conditions. So we use the context aware computing to actualize the cluster head node, the routing path choosing. In this paper, we consider a novel routing protocol using the cluster schemes to find the optimal energy routing path based on a special topology structure of Resilient Ontology Multicasting Routing Protocol (RODMRP). The RODMRP is one of the hierarchical ad hoc network structure which combines the advantage of the tree based and the mesh based network. This scheme divides the nodes in different level found on the node energy condition, and the clustering is established based on the levels. This protocol considered the residual energy of the nodes and the total consuming energy ratio on the routing path to get the energy efficiently routing. The proposed networks scheme could get better improve the awareness for data to achieve and performance on their clustering establishment and messages transmission. Also, by using the context aware computing, according to the condition and the rules defined, the sensor nodes could adjust their behaviors correspondingly to improve the network routing.

• Journal of Mechanical Science and Technology
• /
• v.18 no.11
• /
• pp.1996-2008
• /
• 2004

A seamless analysis of material behavior incorporating complex geometry and crack- tip modeling is one of greatly interesting topics in engineering and computational fracture mechanics fields. However, there are still large gaps between the industrial applications and fundamental academic studies due to a time consuming detailed modeling. In order to resolve this problem, a numerical method to calculate an energy release rate by virtual crack closure technique was proposed in this paper. Both free mesh method and finite element method have been utilized and, thereafter, robust local and global elements for various geometries and boundary conditions were generated. A validity of the proposed method has been demonstrated through a series of fracture mechanics analyses without tedious crack-tip meshing.

• Journal of the Korean Dietetic Association
• /
• v.15 no.2
• /
• pp.179-187
• /
• 2009

In this study, we examined whether the glycemic index (GI) values of boiled white rice (GI=86) and boiled white rice mixed with grains (GI=58) could influence the total energy intake and satiety rate of a rice-based diet. Thirty adult females participated in this study, in which they ate boiled white rice, or boiled white rice mixed with grains, along with side dishes for lunch, and then ate the same white rice diet for dinner in the lab once a week for 2 weeks. There was no significant difference in the visual analogue scales for taste between the two diets. Although there were no differences between the subjects' energy intakes for side dishes, the total energy consumed from the boiled white rice mixed with grains diet (520.5 kcal) was significantly (p<0.001) lower than that consumed from the boiled white rice diet (560.2 kcal). For dinner, the subjects consumed significantly (p<0.001) lower calories when they had eaten the boiled white rice mixed with grains diet for lunch as compared to the boiled white rice diet. In addition, the subjects reported significantly (p<0.01, p<0.001) higher satiety rates after consuming the boiled white rice mixed with grains diet compared to the boiled white rice diet, despite consuming lower calories. In conclusion, these results indicate that consuming low GI rice such as boiled white rice mixed with grains substituted for boiled white rice, may be a useful strategy for weight loss and weight management since individuals will consume less energy without experiencing a reduction in satiety.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.9 s.114
• /
• pp.904-911
• /
• 2006

A modified energy method for the fretting wear of the steam generator tube is proposed to calculate the wear-out depth between the nuclear steam generator tube and its support. Estimation of fretting-wear damage typically requires a non-linear dynamic analysis with the information of the gap velocity and the flow density around the tube. This analysis is very complex and time consuming. The basic concept of the energy method is that the volume wear rate due to the fretting-wear phenomena Is related to work rate which is time rate of the product of normal contact force and sliding distance. The wearing motion is due to dynamic interaction between vibrating tube and its support structure, such as tube support plate and anti-vibration bar. It can be assumed that the absorbed work rate would come from turbulent flow energy around the vibrating tube. This study also numerically obtains the wear-out depth with various wear topologies. A new dissection method is applied to the multi-span tubes to represent the vibrational mode. It turns out that both the secondary side density and the normal gap velocity are important parameters for the fretting-wear phenomena of the steam generator tube.

• Earthquakes and Structures
• /
• v.17 no.4
• /
• pp.387-398
• /
• 2019

On the basis that ground motions may arrive at a structure from any horizontal direction and that different directions of seismic incidence would result in different structural dynamic responses, this paper focuses on orienting the crucial seismic incidence of transmission tower-line systems based on the wavelet energy method. A typical transmission tower-line system is chosen as the case study, and two finite element (FE) models are established in ABAQUS, with and without consideration of the interaction between the transmission towers and the transmission lines. The mode combination frequency is defined by considering the influence of the higher-order modes of the structure. Subsequently, wavelet transformation is performed to obtain the total effective energy input and the effective energy input rate corresponding to the mode combination frequency to further judge the critical angle of seismic incidence by comparing these two performance indexes under different seismic incidence angles. To validate this approach, finite element history analysis (FEHA) is imposed on both FE models to generate comparative data, and good agreement is found. The results demonstrate that the wavelet energy method can forecast the critical angle of seismic incidence of a transmission tower-line system with adequate accuracy, avoiding time-consuming and cumbersome computer analysis. The proposed approach can be used in future seismic design of transmission tower-line systems.