• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.406-408
• /
• 2000

Recently, Korea's electric industry is in the midst of a period of profound changes in the structure and function, including the introduction of market competition in the generation sector. Therefore, it is difficult to promote long-term capacity planning and new generating capacity construction which have been driven by KEPCO so far, after the introduction of market competition, so new generating capacity construction and security of reserve margin is needed through self·regulation plan of private generation producers by market mechanism. According to the competition in the generation sector, a new paradigm is necessary to the long-term capacity planning driven by the Government. This paper analyzes the plan and the incentive level able to guide the new generation capacity construction considering the uncertainty risk in a period of introduction of competition. In addition, this paper analyzes the plan able to guide the new capacity construction by market function at the stage which market become established and Government's role to solve the anxiety about the capacity supply and demand.

• The Korean Journal of Food And Nutrition
• /
• v.27 no.1
• /
• pp.112-119
• /
• 2014

Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch's thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. Herein, we have studied thermal property changes of wheat, corn, potato and sweet potato starch by ohmic heating as well as conventional heating. And then we measure the water holding capacity of starches. Annealing of starch is a heat treatment method heated at 3~4% below the gelatinization point. This treatment changes the starch's thermal property. In the DSC analysis of this study, the $T_o$, $T_p$, $T_c$ of all starch levels have increased, and the $T_c$-$T_o$ narrowed. In the ohmic heating, the treatment sample is extensively changed but not with the conventional heating. From the ohmic treatment, increases from gelatinization temperature are potato ($8.3^{\circ}C$) > wheat ($5.3^{\circ}C$) > corn ($4.9^{\circ}C$) > sweet potato ($4.5^{\circ}C$), and gelatinization ranges are potato ($7.9^{\circ}C$), wheat ($7.5^{\circ}C$), corn ($6.1^{\circ}C$) and sweet potato ($6.8^{\circ}C$). In the case of conventional treatment, water holding capacity is not changed with increasing temperature but the ohmic heating is increased. Water holding capacity is related to the degree of gelatinization for starch. This result show that when treated with below gelatinization temperature, the starches are partly gelatined by ohmic treatment. When viewing the results of the above, ohmic treatment is enhanced by heating and generating electric currents to the starch structure.

• The Korean Journal of Physiology
• /
• v.14 no.1
• /
• pp.7-13
• /
• 1980

In the previous experiment, authors have shown that during the latter half of estrous cycle there was an increase in plasma testosterone level in the rats stimulated with hCG. To determine the physiologic significance of elevated plasma testosterone, changes of the plasma concentrations of TeBG and testosterone following hCG stimulation were analyzed in the rats having a regular 5 day cycle. The rats were divided into three groups; the control, the rats stimulated with single hCG on the day of proestrus and stimulated with hCG throughout the entire cycle. Blood samples were obtained once a day for an estrous cycle and analyzed for the binding capacity of TeBG using ammonium sulphate precipitation method and testosterone concentration by means of radioimmunoassay. Followings were the results; 1) There was no significant variation in the binding capacity of TeBG in peripheral blood during the estrous cycle of the control rats. 2) No cyclic variation in the binding capacity of TeBG was observed in the rats stimulated with single hCG on proestrus. although the levels tended to be higher in the rats with stimulation than in the control rats. 3) Continual stimulation of hCG produced a marked increase in the binding capacity of TeBG especially on the day of metaestrus. 4) The changes in the plasma level of testosterone followed the same basic pattern seen in the TeBG binding capacity. 5) From above results, the followings were suggested. a. hCG related increase of the binding capacity of TeBG is probably secondary to a modest increase in estrogen as well. b. hCG related increase of plasma testosterone in female rats is not entirely due to excess production rather in part due to decreased metabolism induced by the rise in TeBG. c. It seems likely that most of elevated testosterone shown in the rat stimulated with hCG is bound to TeBG and only small portion is unbound form which influence cellular activity. It is rather possible that an increase in TeBG could augment estrogen activity.

• Journal of the Korean Society for Railway
• /
• v.8 no.6 s.31
• /
• pp.507-512
• /
• 2005

Railroad transportation system has experienced major changes due to KTX introduction. Kyungbu corridor especially Seoul to Cheonan has line capacity problem and its solution has been a primary concern to researchers and policy decision makers. This study explored pattern of train operation between Seoul and Cheonan after the introduction of KTX in 2004. Both the number of trains and available seat capacity per day have increased but maximum number of trains per specific hour has not been changed much. Demand for train shows that if concentrated in a specific time, so number of trains during the peak hour should be increased. But, it is difficult ? 새 line capacity, so increasing seat capacity per train might be an option. An increase in an avaliable sear should be considered the characteristics of each train lines.

• Journal of Power Electronics
• /
• v.13 no.3
• /
• pp.497-506
• /
• 2013

This paper proposes a new method to improve the available battery capacity in electric vehicles by connecting lead-acid batteries with lithium-ion battery in parallel to supply power. In addition, this method combines the discharge characteristics of batteries to improve their efficiency and lower their cost for electric vehicles. A lithium-ion battery set is used to connect with N sets of lead-acid batteries in parallel. The lead-acid battery supplies the initial power. When the lead-acid battery is discharged by the load current until its output voltage drops to the cut-off voltage, the power management unit controls the lead-acid battery and changes it to discharge continuously with a small current. This discharge can be achieved by connecting the lead-acid battery to a lithium-ion battery in parallel to supply the load power or to discharge its current to another lead-acid or lithium-ion battery. Experimental results demonstrates that the available capacity can be improved by up to 30% of the rated capacity of the lead-acid batteries.

• Journal of Korea Port Economic Association
• /
• v.33 no.3
• /
• pp.105-120
• /
• 2017

This study analyzed changes in the competitive structure of the global shipping container market and the appropriate capacity of the container fleet in Korea from three perspectives. The competitive market analysis applied the market concentration ratio and Hirschman-Herfindahl index, while the appropriate capacity analysis was based on the following three aspects: (1) Fleet capacity to secure competitiveness in the global shipping alliance; (2) Fleet capacity to increase national fleet coverage of domestic import and export container cargo; and (3) Fleet capacity analysis through the panel model considering the characteristics of the major shipping countries. Analysis of the global shipping container market reveals an oligopoly industry, and Korea's container fleet capacity is insufficient across all three analyses.

• Steel and Composite Structures
• /
• v.47 no.3
• /
• pp.437-450
• /
• 2023

A half open cross section built-up column, namely cold-formed thin-walled steel built-up column with 12-limbsection (CTSBC-12) is put forward. To deeply reveal the mechanical behaviors of CTSBC-12 under axial compression and put forward its calculation formula of axial bearing capacity, based on the previous axial compression experimental research, the finite element analysis (FEA) is conducted on 9 CTSBC-12 specimens, and then the variable parameter analysis is carried out. The results show the FEA is in good agreement with the experimental research, the ultimate bearing capacity error is within 10%. When the slenderness ratio is more than 96.54, the ultimate bearing capacity of CTSBC-12 decreases rapidly, and the failure mode changes from local buckling to global buckling. With the local buckling failure mode unchanged, the ultimate bearing capacity decreases gradually as the ratio of web height to thickness increases. Three methods are used for calculating the ultimate bearing capacity, the direct strength method of AISI S100-2007 gives result of ultimate axial load which is closest to the test and FEA results. But for simplicity and practicality, a simplified axial bearing capacity formula is proposed, which has better calculation accuracy with the slenderness ratio changing from 30 to 100.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.51 no.6
• /
• pp.290-295
• /
• 2002

The present assignment in installing the number of switches for distribution line was made on the basis of a normal feeder capacity 7,000kVA in KEPCO(Korea Electric Power Corporation), Korea. But the normal capacity is revised to 10000kVA in 1998. Even increasing limit of the operating capacity of the distribution lines enables us to give some benefit for the operation flexibility and investment cost of the distribution system. It is disadvantageous in the viewpoint of supply reliability. In distribution systems, switches are equipped to improve the reliability of distribution systems by minimizing the outage section due to fault and maintenance. Utility generally improves the reliability by minimizing the length of outage section, which is caused by fault and maintenance, through switch equipment on distribution system. In order to cope with the changes such as operation capacity, it is necessary to study whether the present criteria is reasonable or not, also to confirm whether the present criteria of installing switches in line is improved or not. In this study, we proposes the number of switch per feeder on the basis of present operation capacity in distribution system.

• The Korean Journal of Ecology
• /
• v.19 no.5
• /
• pp.453-463
• /
• 1996

Diurnal changes of microclimatic conditions and tissue water relations were measured at two sites where Carpinus laxiflora and C. cordata were allopatrically distributed. The microclimatic conditions at a site where C. laxiflora was distributed produced severe water stress condition during summer months. Daily maximum temperature reached $30.4^\circC$ and the highest vapor pressure deficit was 1.31 KPa when 13 rainless days were continued. During this period soil water content decreased to below the field capacity even at a depth of 20 cm and xylem pressure potential also decreased to ­2.04 MPa. However, turgor potential was maintained more than 0.4 MPa. Patterns of stomatal conductance were changed with evaporative demand and soil water availability. On the other hand, microclimatic conditions at a site where C. cordata was distributed were moderate water strees condition compared with those at a site C. laxiflora was distributed. Though soil water content was maintained above field capacity C. cordata showed a remarkable decrease in turgor potential and stomatal conductance throughout the experiment. These results indicate that there is a difference in habitat characteristics between the two species and C. laxiflora is more resistant than C. cordata to water stress.

• Water Engineering Research
• /
• v.5 no.1
• /
• pp.17-36
• /
• 2004

This paper evaluated the water resources aspect of the operating results of the Daecheong Multipurpose Dam for the last 21 years. The elements that were evaluated included the amount of water supply from the dam. volume of outflow from the regulating dam, changes in the runoff volume at the dam site and downstream, and variations in the water supply capacity of the Daecheong Multipurpose Dam and the Geum River Barrage Dam situated in the estuary. The rainfall-runoff model was used to evaluate the changes in the runoff volume, and the water balance analysis system was used to evaluate the variations in the dams'water supply capacities. The volume of domestic and industrial water supply from the Daecheong Multipurpose Dam increased to 6.1 times for the last 21 years from 61${\times}$$10^6$$m^3$ in 1981 to 375${\times}$$10^6$$m^3$in 2001. The rate of outflow to inflow of the Daecheong Dam was analyzed 1.30 times in dry season, 1.12 times in semi-dry season, and 0.90 times in rainy season. The volume of inflow to the Geum River Barrage Dam down- stream after the dam's construction increased to 1.25 times in dry season and 1.02 times in semi-dry season and decreased to 0.94 times in rainy season. The water supply capacity of the estuary barrage dam almost did not change in cases with or without the Daecheong Multipurpose Dam, but storages were largely affected by the outflows of the Daecheong Multipurpose Dam.