• Journal of Electrical Engineering and Technology
• /
• v.8 no.3
• /
• pp.393-401
• /
• 2013

This paper deals with the operation strategy of the Cheju AC network included MIHVDC system (Multi-Infeed HVDC system). In case that where several HVDC systems are located in the vicinity of each other, there are interactions between the different HVDC systems in such network configurations. The interactions which could be generated in multi-infeed HVDC are voltage stability, power stability and inertia stability, to analyze such systems in a systematic way to ensure that there are no risks of adverse interactions is very important. The developed method until now to analyze MIHVDC interaction is extended from MAP(Maximum Available Power) method for analyzing the power stability of the single-infeed HVDC system, this method is to solve the eigenstructure using the identified factors influencing the interactions. Finally, the algorithms which are introduced in this paper, to determine the operation strategy are applied to Cheju island network which is supplied by two HVDCs.

• Journal of the Korean Society for Railway
• /
• v.6 no.3
• /
• pp.156-162
• /
• 2003

Due to almost all tracks of new Kyoungbu high-speed lines(HSL) consisting of bridges and tunnels, HSR operational safety management is very important factor for passenger safety and preventing catastrophic event. Especially, it is important to approach the scene of the accident and assist in saving lives as soon as possible under emergency conditions. Therefore it is essential to prepare access methods and available resources in advance in order to support emergency correspodances promptly and effectively. This paper persents an application of geographical information system(GIS) for developing emergency management system as well as batabase system on tracks and facilities, electric/communication equipment and safety equipment required to support emergencies. The on-site information on the proximity of HSL is expressed on the numerical map, which can be helpful to call external supports such as medical service, local authorities, police offices, fire brigades, and etc. for the emergency situations.

• IE interfaces
• /
• v.14 no.1
• /
• pp.59-66
• /
• 2001

This paper introduces the case study that has been performed at the block paint shop, Hyundai Heavy Industries. First of all, the overall production processes of shipbuilding and research activities conducted by Korean are reviewed with a view-point of production planning. Then HYPOS(Hyundai heavy industries Painting shop Operation System) project is briefly described, which has several modules such as planning module, scheduling module, work order module, and DB(database) management module. Although the HYPOS system has several modules, this paper mainly focuses on the planning module that utilizes the rough-cut simulation algorithm to make a decision about the policy for production schedule. The HYPOS has been operated since June, 2000 and the operation data has been collected for the purpose of future evaluation about the performance of HYPOS system. The evaluation of HYPOS will be shown in a public domain as soon as the enough operation data is available.

• Proceedings of the KSRS Conference
• /
• 2003.11a
• /
• pp.588-590
• /
• 2003

For the normal operations, KOMPSAT-1 orbits are determined using GPS navigation solutions data such as position and velocity vectors. Currently, the accuracy of GPS navigation solution data is generally known as on the order of 10~30 m with the removal of S/A. In this paper, an estimate of the current orbit determination accuracy for the KOMPSAT-1 is given. For the evaluation of orbit determination accuracy, the orbit overlap comparison is used since no independent orbits of comparable accuracy are available for comparison. As a result, It is shown that the orbit accuracy is on the order of 5 m RMS with 4 hrs arc overlap for the 30 hr arc.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.57-62
• /
• 2006

Busan New Port, under construction aiming for the hub of Northeast Asia and Partly in operation, had damaged up to 48 billion Won due to Typhoon 'maemi' in 2003. The present criteria of domestic harbor design only describes about the critical wave height with respect to the size of vessel for harbor tranquility. The berth operation ratio which represents the annual available berthing days is depending on the efficiency of cargo handling work and this depends on the motion of the moored vessel due to the wave action and the characteristics of cargo gears. The motion of moored vessel might be related not only to the wave height but also to wave period. Furthermore, the berth operation ratio relies on external forces such as currents and winds, including the characteristics of mooring system and the specification of the moored vessel. In this study we only deal with berth operation ratio in normal sea state, considering wave and current by measured data and numerical calculation. Especially we tried to evaluate the berth operation ratio for each berth adopting the variation of dredging and reclamation plan and the change of wave environment during the process of the new port construction. For better understanding and analysis of wave transformation process, we applied the steady state spectral wave model and extended mild-slope wave model to the related site. This study summarizes comparisons of harbor responses predicted by two numerical predictions obtained at Busan New port site. Field and numerical model analysis was conducted for the original port plan and the final corrected plan.

• Journal of the Korea Safety Management & Science
• /
• v.10 no.4
• /
• pp.73-81
• /
• 2008

The current electrical safety plan developed for the national electricity system has been playing an important role in handling a variety of electrical accidents. However, it can be more effective to prevent or reduce those accidents if a preventive electrical safety plan is available. In this paper, an approach to developing the safety plan is described. We first discuss the contents that should be included in the plan. Noting that an effective plan requires the system level consideration of all the factors affecting the safety issues, an operation concept document (OCD) is considered. The OCD can allow us to understand the behavior of the safety system based on the operation environment, the system functions, the performance requirements, all at the system level of the safety system. Thus, the OCD can be useful in developing the safety plan. A detailed description then follows on how the OCD is developed for the electrical safety system under study. Finally, we discuss how the developed OCD can be used in deriving the preventive electrical safety plan.

• Advances in pediatric surgery
• /
• v.13 no.1
• /
• pp.61-65
• /
• 2007

Conventional treatment of Hirschsprung's disease consists of initial colostomy followed by pull-through operation. But, the treatment of Hirschsprung's disease has been changed along with the development of new surgical technique. Since 1995, endo-GIA has been available at our hospital and one stage Duhamel operation has been performed for neonatal Hirschsprung's disease. Between May 1995 and April 2006, 26 neonates have been treated with one stage pull-through operation by one pediatric surgeon at HanYang University Hospital. The sex ratio was 4.2:1 with male predominance. Clinical findings included abdominal distension (96.2 %), vomiting (50.0 %), delayed passage of meconium (46.2 %), constipation (23.1 %), and enterocolitis (15.4 %). Twenty two cases (84.6 %) were short-segment and 4 cases (15.4 %) were long-segment disease, of which 2 cases were total colon aganglionosis. One of the two patients with total colonic aganglionosis had double transition zones - distal ileum and hepatic flexure of the colon. The average age at operation was $14.56{\pm}8.77$ days and the average weight at operation was $3.26{\pm}0.66kg$. Primary Duhamel operations were performed in 25 patients and Soave-Boley operations was performed in one patient. The endo-GIA 35 (Ethicon, USA) was used from 1995 until 1997, and after that endo-GIA 60 (USSC, USA) was used. The average Duhamel operation time was $88.57{\pm}22.80$ minutes. Wound abscess (n = 2) and septum formation (n =1) occurred after Duhamel operation. Bowel function was normalized in 59 % within 3 months and in 95% within 1 year after operation. There was no mortality after one stage pull-through operation in neonate.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.3
• /
• pp.1337-1345
• /
• 2012

The principle of Effective Based Operation applied to the Korean Theater resulted in measurable effects to win the minimum battle. Based on the finding, this study recommends the effect analysis methodology under the V-C interoperability system to acquire a weapon system. This method is followed as below; to confirm the effect data on the organized weapon system, to set MOE, MOP and effect considering the purpose of the analysis, to apply the appropriate operational concept and scenario on the weapon system, and then the available C Model is after action reviewed, adjusted, and given feedback. The V-C interoperability system enables to perform the real-time combat experiment under the virtual synthesized battlefield circumstances. The defensive battle organization and displacement of the future anti-tank guided weapon system was considered in the modeling process. Scenario was written, which encompasses company-level units and the battalion-level operation. Then the available AWAM was embodied and effect-analyzed, which formed the foundation of SBA.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.3 no.2
• /
• pp.156-164
• /
• 1998

The operation regions of a three-phase(3Ø) voltage-source(VS) PWM converter are classified in the current vector plane of the synchronous reference frame and their characteristics are explained. In the the power-factor decreasing region, the current control with unity power-factor can not give satisfactory performance to the given load because of the distortion of input current and the ripples and the steady-state errors in DC link voltage. In this paper, the derivation of the optimal current vector is proposed to solve these problems. With this, the input current can be controlled sinusoidally with available maximum power factor and the DC link voltage be the given load, resulting the expansion of the operation region of the 3Ø VS PWM converter. The validity of the proposed control method is proved by the experimental results.

• International Journal of Highway Engineering
• /
• v.16 no.3
• /
• pp.75-84
• /
• 2014

PURPOSES : Traffic congestions which occur in the intersections of arterials lead to mobility and environment problem, and then traffic agencies and engineers have been struggling for mitigating congestions with greenhouse gas emissions. As an alternative of solving theses problems, this study is to introduce a low-cost and high-effectiveness countermeasure as unconventional intersections which are successfully in operation in U.S.. The main feature of unconventional intersections is to reroute turning movement on an approach to other approach, which consequently more green time is available for the progression of through traffic. Due to improved progression, this unique geometric design contributes to reduce delays with greenhouse gas emission and provides a viable alternative to interchanges. This study is to evaluate the potential operation and environment benefits of unconventional intersections. METHODS : This study used the VISSIM model with Synchro and EnViVer. Synchro is to optimize signal phases and EnViVer model to estimate the amount of greenhouse gas emissions by each condition. RESULTS : The result shows that unconventional intersections lead to increase the capacity and to reduce greenhouse gas emissions, compared to existing intersections. CONCLUSIONS : Unconventional intersections have the ability to positively impact operations and environments as a low-cost and high-effectiveness countermeasure.