• Journal of Korean Society of Forest Science
• /
• v.106 no.1
• /
• pp.54-62
• /
• 2017

This study was carried to develop the chip-harvester and to analysis the operation productivity and cost for effective collection and forwarding of forest biomass. Main target specification of chip-harvester is speed of 8km/h, maximum climbing capacity of $30^{\circ}$ and maximum load capability of 2000 kg. Body structure is articulate type to reduce turning radius. Driving equipment is six-wheel drive, and a rear wheel is tandem bogie type to increase grip force. As a result of the driving test about developed chip-harvester, driving speed was 6.9 km/hr and 8.1 km/hr in ${\pm}10%$ slope with loaded and 7.3 km/hr and 7.9 km/hr in ${\pm}10%$ slope without load. As a result of the operation productivity and cost, operation productivity of grinding and forwarding was approximately $10m^3$ per day, and operation cost was 393,126 won per day.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.48 no.8
• /
• pp.932-940
• /
• 1999

This paper discusses the development of an interactive and graphic software for the education and training of power system operation and control, especially for students and beginners. This software has a lot of functions for users to simulate the power system operation and control with ease. These functions included in this software are followings. First, this software includes a Graphic User Interface (GUI) - which contains interactive simulation scheme, Windows dialog box, graphic representations, and graphic icons - so that users can handle the software in user-friendly environments. Second, it uses a graphic editor so that users can easily edit the one-line diagram of the power system. Third, it prepares a database system so that users can manage the power system data for simulation easily. Fourth, the application modules included in the software are the Economic Dispatch (ED) and the Automatic Load-Frequency Control (ALFC). These application modules are designed as independent modules. Using the ED module, users can understand the basic concepts of the ED with ease. And using the ALFC module, they can easily acquire the basic understanding of the response of the ALFC between the two-area systems. The proposed software is tested on both the 16 bus and the two-area sample system. The test has confirmed the functions of the developed software. It is anticipated that the software will be useful for the education and training of power system operation and control for the power engineering study at university or for the training of the beginner at power industry.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.6
• /
• pp.1183-1194
• /
• 2021

Traditionally, electric power systems have been known as the centralized structures, which is organized into placing customers at the end of the supply chain. However, recent decades have witnessed the emergence of distributed energy resources(:DERs) such as rooftop solar, farming PV system, small wind turbines, battery energy storage systems and smart home appliances. With the emergence of distributed energy resources, the role of distributed system operators(:DSOs) will expand. The increasing penetration of DERs could lead to a less predictable and reverse flow of power in the system, which can affect the traditional planning and operation of distribution and transmission networks. This raises the need for a change in the role of the DSOs that have conventionally planned, maintained and managed networks and supply outages. The objective of this research is to designed the future distribution operation system with multi-DERs and the proposed distribution system model is implemented by hardware-in-the-loop simulation(HILS). The test results show the normal operation domain and reduction of distribution line loss.

• Journal of Korea Trade
• /
• v.27 no.3
• /
• pp.65-86
• /
• 2023

Purpose - As globalization progresses, complexity also increases, and various factors that threaten port functions are emerging. Accordingly, the demand for port security to prevent the crisis and resilience that quickly recovers its original function after the crisis is also increasing in port operations. However, few studies have examined how to ensure the port security and how the resilience affects operation performance of port and sustainability performance as well. So the study aims to find out how port security affects port resilience and port operational performance, and consequently, this two factors affect socioeconomic and environmental sustainability performance respectively and synthetically. Design/methodology - Confirmatory Factor Analysis (CFA) was first performed to determine the validity of the factors of model and hypothesis test was performed using Structural Equation Model (SEM) to analyze the Port Performance Model, which show the perception logic among port security level, port resilience, operation performance, and sustainability performance. In order to empirically analyze this model, total 264 respondents from port security operators, shipping companies in South Korea were surveyed. Findings - As result of SEM, First, port security level positively affected the resilience (H1) and cargo operational performance (H2) but not in both of the sustainability performances (H3, H4). Second, resilience positively affected only cargo operational performance (H5) and socio-economic sustainability performance (H7). Last, cargo operation performance positively affects the both of sustainability performances (H8, H9). Originality/value - It was confirmed that port security could improve cargo operational performance through ensuring port resilience and eventually increase the socio-economic sustainability. Therefore the study implies that careful integration and management of port security, port resilience, and sustainability are required, along with compromise on sustainable development goals in the social, economic, and environmental area among all stakeholders.

• Journal of Astronomy and Space Sciences
• /
• v.41 no.1
• /
• pp.43-60
• /
• 2024

Korea Pathfinder Lunar Orbiter (KPLO) is South Korea's first space exploration mission, developed by the Korea Aerospace Research Institute. It aims to develop technologies for lunar exploration, explore lunar science, and test new technologies. KPLO was launched on August 5, 2022, by a Falcon-9 launch vehicle from cape canaveral space force station (CCSFS) in the United States and placed on a ballistic lunar transfer (BLT) trajectory. A total of four trajectory correction maneuvers were performed during the approximately 4.5-month trans-lunar cruise phase to reach the Moon. Starting with the first lunar orbit insertion (LOI) maneuver on December 16, the spacecraft performed a total of three maneuvers before arriving at the lunar mission orbit, at an altitude of 100 kilometers, on December 27, 2022. After entering lunar orbit, the commissioning phase validated the operation of the mission mode, in which the payload is oriented toward the center of the Moon. After completing about one month of commissioning, normal mission operations began, and each payload successfully performed its planned mission. All of the spacecraft operations that KPLO performs from launch to normal operations were designed through the system operations design process. This includes operations that are automatically initiated post-separation from the launch vehicle, as well as those in lunar transfer orbit and lunar mission orbit. Key operational procedures such as the spacecraft's initial checkout, trajectory correction maneuvers, LOI, and commissioning were developed during the early operation preparation phase. These procedures were executed effectively during both the early and normal operation phases. The successful execution of these operations confirms the robust verification of the system operation.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2003.03a
• /
• pp.365-368
• /
• 2003

Despite of the simple equipment and operation, DMT has been widely used to obtain various soil parameters and those parameters have been successfully applied to geotechnical design practice. Among them, the estimation of horizontal coefficient of consolidation is so useful that many researchs recently have been carried out. However, simulation of the penetration of the DMT blade is complex due to the inherent difficulty on analyzing a plane strain deformation of the soil around blade. Therefore, empirical and semi-empirical methods that use the theoretical solution developed fur piezocone with some assumptions have been used to estimate the coefficient of consolidation from Dilatometer dissipation test. In this paper, coefficients of consolidation c$\_$h/ which were obtained using equivalent radius that is same area with the DMT blade and optimization technique are compared with those obtained from Oedometer test and other interpretation methods. It was found that a new method used in this study can give more precise horizontal coefficient of consolidation than other methods do.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.337-342
• /
• 2011

A roller rig has been widely used in the study about dynamic stability and railway safety. However, the cost for constructing the roller rig and the difficulty in adjusting the design parameters for vehicle systems lead to the development of a small scale simulator which is cheaper than the large scale test systems and easy to control the parameters affecting dynamic characteristics of the railway vehicle. For the operation of the small scale test system called a small scale simulator, it is required to investigate the performance and characteristics of the system. This could be achieved by a comparative study between an analysis and an experiment. This paper presented the analytical model which could be used for verifying of the test results and understanding of the physical behavior of the dynamic system comprising the small scale bogie and the simulator.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1364-1371
• /
• 2011

Advanced EMU completed a production of test train, composed of 6 cars, after 5 years of development process, and it is currently under the process of integrated test and evaluation to inspect performance of car system, efficiency of transport, safety, punctuality, energy efficiency in accordance with urban railways act at Daebul test line. Advanced EMU was produced under consideration of transportation capacity, maintainability, reliability, energy saving, convenience of passengers, and traffic-vulnerables, so it has an epochal difference from former EMU system. And advanced EMU assures operation management from manager's perspective and efficiency of maintenance for practicalization of car and individual equipment. This paper introduces each major equipment of advanced EMU which is based on many years of experience of management and maintenance.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1049-1058
• /
• 2011

This paper suggests blending time adjusting method of braking command characteristics management and Set value test for optimizing of braking deceleration to enhance the precise position stopping. This method minimizes pneumatic-braking degree deviation by characteristics management, and secures braking stability at braking. By Set value test method, braking blending characteristics are analyzed accurately. And by optimal timing tuning at braking blending, It enhanced the precise position stopping with stabilization of deceleration To demonstrate the usefulness of these suggestion, I modeled for Deajeon Line #1. And through comparison with case of related companies, the proposed method which this paper suggested is proved to be superior to others.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.145-145
• /
• 2009

In this paper, we suggest how to adapt RFID system to train switching process, and then what we get the merit or problem. We analyze the train switching process to adapt RFID system on the process and have field test. The role of RFID system in train switching process is to automatically read car position information. The specification of the test system is 900MHz, and Gen2 passive tag. If we get the system which automatically read car position information in train switching yard, it prevents human errors and makes more reliability, the performance of train operation will grow up. Even though the environment of train switching yard is outdoors, the test result gives us the ability to adapt RFID system to train switching process and the process will be more simple.