• Journal of the Korea Concrete Institute
• /
• v.24 no.1
• /
• pp.45-52
• /
• 2012

A variety of retrofit material such as CFRP, GFRP, and PolyUrea have been developed for strengthening RC structures and infrastructures. From previously reported research results, the capacity of strengthened concrete structures was dictated by the behavior of the interface between retrofit material and concrete. In this study, bond-shear test was carried out to estimate the bond behavior between retrofit material and concrete using a newly developed test grip. The test results of load and slip relation and energy absorption capacity of each retrofit material were obtained. These test results will provide basic information for retrofit material selection to achieve target retrofit performance.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.10
• /
• pp.1390-1396
• /
• 2013

The paper estimated the reasonable market price of lead-acid battery energy storage system (BESS) intended for demand management of electricity customers. As time-of-use (TOU) tariffs have extended to a larger number of customers and gaps in the peak and off-peak rates have gradually risen, deployment of BESS has been highly needed. However, immature engineering techniques, lack of field experiences and high initial investment cost have been barriers to opening up ESS markets. This paper assessed electricity cost that BESS operation could save for customers and, based on the possible cost savings, estimated reasonable prices at which BESSs could become a more prospective option for demand management of customers. Battery scheduling was optimized to maximize the electricity cost savings that BESS would possibly achieve under TOU tariffs conditions. Basic economic factors such as payback period and return on investment were calculated to determine reasonable market prices. Actual load data of 12 industrial customers were used for case studies.

• The KIPS Transactions:PartA
• /
• v.10A no.6
• /
• pp.635-642
• /
• 2003

The radical development of recent network technology provides the basic foundation which can establish a high speed and cheap cluster system. It is a general trend that conventional cluster systems are built as the system over a fixed level based on stabilized and high speed local networks. A multi-distributed web cluster group is a web cluster model which can obtain high performance, high efficiency and high availability through mutual cooperative works between effective job division and system nodes through parallel performance of a given work and shared memory of SC-Server with low price and low speed system nodes on networks. For this, multi-distributed web cluster group builds a sub-cluster group bound with single imaginary networks of multiple system nodes and uses the web distributed shared memory of system nodes for the effective data transmission within sub-cluster groups. Since the presented model uses a load balancing and parallel computing method of large-scale work required from users, it can maximize the processing efficiency.

• Journal of Korean Society of Transportation
• /
• v.22 no.2 s.73
• /
• pp.109-119
• /
• 2004

In COSMOS, an area for signal coordination is divided into subareas composed of several signalized intersections that share a common cycle time. Each subarea contains only one critical intersection having heavy traffic load. Subarea is a basic unit of control. The performance of COSMOS is highly dependent on the linkage rule between adjacent subareas. The purpose of this study is to provide an appropriate subarea linkage rule in COSMOS. This study developed a control strategy for Critical Intersection and Sub Area linkage. Critical Intersections calculate the Offset Pattern both East-West Axis and North-South Axis, and the coordination direction either East-West Axis or North-South Axis. Subarea can be combined with other one in all directions. The performance of the suggested linkage rule was evaluated on the real network in Gangnam-Gu. The result was that travel time was reduced by the suggested linkage rule.

• Wind and Structures
• /
• v.19 no.3
• /
• pp.339-352
• /
• 2014

This paper discusses the appropriate duration for basic gust wind speeds in wind loading codes and standards, and in wind engineering generally. Although various proposed definitions are discussed, the 'moving average' gust duration has been widely accepted internationally. The commonly-specified gust duration of 3-seconds, however, is shown to have a significant effect on the high-frequency end of the spectrum of turbulence, and may not be ideally suited for wind engineering purposes. The effective gust durations measured by commonly-used anemometer types are discussed; these are typically considerably shorter than the 'standard' duration of 3 seconds. Using stationary random process theory, the paper gives expected peak factors, $g_u$, as a function of the non-dimensional parameter ($T/{\tau}$), where T is the sample, or reference, time, and ${\tau}$ is the gust duration, and a non-dimensional mean wind speed, $\bar{U}.T/L_u$, where $\bar{U}$ is a mean wind speed, and $L_u$ is the integral length scale of turbulence. The commonly-used Durst relationship, relating gusts of various durations, is shown to correspond to a particular value of turbulence intensity $I_u$, of 16.5%, and is therefore applicable to particular terrain and height situations, and hence should not be applied universally. The effective frontal areas associated with peak gusts of various durations are discussed; this indicates that a gust of 3 seconds has an equivalent frontal area equal to that of a tall building. Finally a generalized gust response factor format, accounting for fluctuating and resonant along-wind loading of structures, applicable to any code is presented.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.31 no.3
• /
• pp.93-102
• /
• 1989

With an objective to provide basic information for the management and the prediction of eutrophication in lentic water Systems, total amount of Kjeldahl nitrogen(T-N) and phosphorous(T-P) from irrigated water and drained water from flooded paddies were investigated during the rice growing period of 1988. A 29.3 ha paddies near Jungnam-myun, HwaSung-gun, Gyungi Province, Korea was instrumented for measuring runoff and sampling irrigated water and drained water from paddies. The following conclusions may be drawn from the result of this study. 1.During 115 days of investigation, T-N load for paddies was 362.6kg and T-P 63.44kg.These would be converted to 12.4kg T-N/ha and 2.17kg T-P/ha, respectively. 2.The T-N and T-P loadings in different periods showed a significant difference. The 25% of T-N loading was drained soon after fertilization period and 60% was drained during the rainy season from July 5 to July 24. 3.Annual loadings from paddies could be calculated to 30kg T-N/ha/year and 52kg T-P/ha/year considering non-measurement periods. 4.After the rainy season, the nutrient loads from drained water showed much less than those from irrigated water, and it may be suggested that the paddies would act as a stabilization pond. 5.The average concentrations of nutrients at 0.9km downstream from investigated paddies were 2.02(T-N) mg/l and 0.52(T-P) mg/I, which were 1.82(T-N) mg/l and 0.056(T-P)mg/l lower than those of drained water from paddies.

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.940-947
• /
• 2018

The purpose of this study was to obtain data to support applied motions of bench press and to provide basic data for the efficient execution of the exercise by analyzing muscular activation through measuring electromyogram of pectoralis major and erector spinae when flat bench pressing with feet on the ground versus feet on the bench. For this study, 4 amateur bodybuilders and 2 health trainers were chosen as subjects. Surface electrodes were attached on the measuring muscles; pectoralis major and erector spinae. Motion phases were defined for the flat bench press and each subject, with a 10RM load, performed a set with feet on the ground and another set with feet on the bench. Data was analyzed in SPSS 20.0 and the following results were obtained. The placement of the feet did not affect the muscular activation of the pectoralis major during the flat bench press. however, the muscular activation of the erector spinae was different between the two positions.

• Journal of Nutrition and Health
• /
• v.35 no.1
• /
• pp.78-89
• /
• 2002

This study was performed to analyse some rick ffactors for chronic degenerative diseases of the Korean dict. The study subjects consisted of preschool children(PC), elementary school children(EC), high school students(HS), college students(CS), and adults over 30 years old living in Seoul and the surrounding areas. The subjects over 30 years old were classfied to 30-49 years, 50-69 years, and over 70 years. A dietary survey was conducted using 24-hour recall method and data were collected from 2392 subjects. The dietary risks for chronic degenerative disease such as food sources of fat consumption, high cholesterol intake, low dietary fiber intake, and low calcium intake and high protein intake were analyzed. Younger subjects had more animal fat proportion than older subjects did. HS and CS had the least fat proportion from fishes and shellfishes. Each mean cholesterol intake of PC, EC, HS, and CS was over 300mg/day, and HS load the highest level of 415mg/day. Cholesterol density of the diet of PC was the highest of 175mg/1000kcal and the level decreased when the age increased. The subjects consuming cholesterol over 100 mg/1000kca1 were about 70% of PC and HS. More than 20% of PC, EC, and HS consumed calcium under 75% of RDA with protein consumption over 125% of RDA. Dietary fiber intakes were 18g for HS, CS, 30-49 years, and 50 ∼ 69 years, 14g for EC and over 70 years, and 12g for PC. Ninety percent of PC and EC, 80% of HS and CS, and 70% of tole subjccts over 30years consumed dietary fiber under the level of 10g/1000kca1. The major food sources of dietary fiber were vegetables and grains. From these results, children and adolescents had ricks for chronic degenerative diseases on all the analyzed items. The results of this study would provide the basic information for development of dietary interventions to improve diet find health.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.5
• /
• pp.450-463
• /
• 2000

Array redistribution is usually required to enhance algorithm performance in many parallel programs on distributed memory multicomputers. GEN_BLOCK redistribution, which is redistribution between different GEN_BLOCKs, is essential for load balancing. However, prior research on redistribution has been focused on regular redistribution, such as redistribution between different CYCLIC(N)s. GEN_BLOCK redistribution is very different from regular redistribution. Message passing in regular redistribution involves repetitions of basic message passing patterns, while message passing for GEN_BLOCK redistribution shows locality. This paper proves that two optimal condition, reducing the number of communication steps and minimizing redistribution size, are essential in GEN_BLOCK redistribution. Additionally, by adding a relocation phase to list scheduling, we make an optimal scheduling algorithm for GEN_BLOCK redistribution. To evaluate the performance of the algorithm, we have performed experiments on a CRAY T3E. According to the experiments, it was proven that the scheduling algorithm shows better performance and that the conditions are critical in enhancing the communication speed of GEN_BLOCK redistribution.

• Computers and Concrete
• /
• v.17 no.1
• /
• pp.1-27
• /
• 2016

Final construction project cost is significantly determined by construction rate. The Industrialized Building System (IBS) was promoted to enhance the importance of prefabrication technology rather than conventional methods in construction. Ensuring the stability of a building constructed by using IBS is a challenging issue. Accordingly, the connections in a prefabricated building have a basic, natural, and essential role in providing the best continuity among the members of the building. Deficiencies of conventional precast connections were observed when precast buildings experience a large induced load, such as earthquakes and other disasters. Thus, researchers aim to determine the behavior of precast concrete structure with a specific type of connection. To clarify this problem, this study investigates the capacity behavior of precast concrete panel connections for industrial buildings with a new type of precast wall-to-wall connection (i.e., U-shaped steel channel connection). This capacity behavior is compared with the capacity behavior of precast concrete panel connections for industrial buildings that used a common approach (i.e., loop connection), which is subjected to monotonic loading as in-plane and out-of-plane loading by developing a finite element model. The principal stress distribution, deformation of concrete panels and welded wire mesh (BRC) reinforcements, plastic strain trend in the concrete panels and connections, and crack propagations are investigated for the aforementioned connection. Pushover analysis revealed that loop connections have significant defects in terms of strength for in-plane and out-of-plane loads at three translational degrees of freedom compared with the U-shaped steel channel connection.