Health Diagnosis of Communities of Practices (CoPs)

The purpose of this study is to provide a multi-level framework to diagnose the structural healthiness of CoPs and present a new metric, Bottleneck Impact Score (BIS), to measure the seriousness of bottlenecks in knowledge sharing activities among CoPs members. After analyzing knowledge sharing activities of 4,414 members from 59 CoPs, we confirm that while only a small number of CoP members actively engage in both transferring and receiving knowledge, most experts are not core players and they are reluctant to share their knowledge with others. We also find that only few CoPs can be classified as knowledge “sharing” community while most of CoPs suffer from inactive participation of employees with high expertise and are diagnosed as having at least one of master-apprenticeship and knowledge drain bottlenecks. Interestingly, we also find that CoPs members in field division such as Iron&Steel, Rolling, and Maintenance department more actively participate in knowledge sharing than CoPs members in Staff department. Finally, BISs are used to measure and compare the seriousness of six different types of bottlenecks in CoPs and departments

Toward Optimal Financial Reward Allocation for Promoting Knowledge Sharing Activity in CoPs

The purpose of this study is to introduce CoP reward allocation (COREA) system that efficiently solves a mathematical optimization problem to optimally allocate limited financial reward and to promote knowledge sharing activities in CoPs. To test the validity and usefulness of COREA, we simulate three knowledge sharing climates in which the majority of CoPs performs below-, on-, or above-average. In addition, we also allow knowledge sharing activity of CoPs to improve or deteriorate over years in each climate. Our experimental results confirm that the proposed COREA system performs significantly better than the currently available reward system over various scenarios. In particular, the COREA system finds approximately optimal financial reward allocations for many cases in which the current reward system fails to find solutions that meet constraints

Round-Trip System Available to Measure Path Length Variation in Korea VLBI System for Geodesy

The construction project of Korea Geodetic VLBI officially started in October 2008. The construction of all systems will be completed by the end of 2011. The project was named Korea VLBI system for Geodesy (KVG), and its main purpose is to maintain the Korea Geodetic Datum. In case of the KVG system, an observation room with an H-maser frequency standard is located in a building separated from the antenna by several tens of meters. Therefore KVG system will adopt a so-called round-trip system to transmit reference signals to the antenna with reduction of the effect of path length variations. KVG s round-trip system is designed not only to use either metal or optical fiber cables, but also to measure path length variations directly. We present this unique round trip system for KVG

The State and Development Direction of the Geodetic VLBI Station in Korea

A permanent geodetic VLBI station with a 22-m diameter antenna will be newly constructed in Korea by the National Geographic Information Institute (NGII) under the project Korea VLBI system for Geodesy (KVG) that aims at maintaining the Korean geodetic datum accurately on the International Terrestrial Reference Frame (ITRF). KVG can receive 2, 8, 22, and 43 GHz bands simultaneously in order to conduct geodetic and astronomical VLBI observations with Korea astronomical VLBI stations along with geodetic observations with IVS stations. This simultaneous four-band receiving capability is a unique feature of the KVG system. The KVG has started officially in October 2008. A new geodetic VLBI station will be constructed at Sejong city (about 120 km south of Seoul and about 20 km north-northwest of Daejeon) and construction of all systems will be completed in 2011

Interaction Boundary Determination of Renewable Energy Sources to Estimate System Strength Using the Power Flow Tracing Strategy

System strength is an important concept in the integration of renewable energy sources (RESs). However, evaluating system strength is becoming more ambiguous due to the interaction of RESs. This paper proposes a novel scheme to define the actual interaction boundaries of RESs using the power flow tracing strategy. Based on the proposed method, the interaction boundaries of RESs were identified at the southwest side of Korea Electric Power Corporation (KEPCO) systems. The test results show that the proposed approach always provides the identical interaction boundaries of RESs in KEPCO systems, compared to the Electric Reliability Council of Texas (ERCOT) method. The consistent boundaries could be a guideline for power-system planners to assess more accurate system strength, considering the actual interactions of the RESs

Development of an integrated engine-hydro-mechanical transmission control algorithm for a tractor

This article presents an integrated engine-hydro-mechanical transmission control algorithm for a tractor considering the engine-hydro-mechanical transmission efficiency. First, the hydro-mechanical transmission efficiency was obtained by network analysis based on the hydrostatic unit efficiency constructed from the test. Using the hydro-mechanical transmission efficiency map and the thermal efficiency of the engine, an engine-hydro-mechanical transmission optimal operating line was obtained, which provides higher total system efficiency. Based on the optimal operating line, an integrated engine-hydro-mechanical transmission control algorithm was proposed, which provides higher total powertrain system efficiency. To evaluate the performance of the proposed control algorithm, an AMESim-MATLAB/Simulink-based co-simulator was developed. From the simulation results for the plow working, it was found that the integrated engine-hydro-mechanical transmission control provides improved fuel economy by 7.5% compared with the existing engine optimal operating line control. The performance of the integrated engine-hydro-mechanical transmission control was also validated using the test bench

Economic Value of Li-ion Energy Storage System in Frequency Regulation Application from Utility Firm’s Perspective in Korea

Energy Storage Systems (ESSs) have recently been highlighted because of their many benefits such as load-shifting, frequency regulation, price arbitrage, renewables, and so on. Among those benefits, we aim at evaluating their economic value in frequency regulation application. However, unlike previous literature focusing on profits obtained from participating in the ancillary service market, our approach concentrates on the cost reduction from the perspective of a utility firm that has an obligation to pay energy fees to a power exchange. More specifically, we focus on the payments between the power exchange market and the utility firm as a major source of economic benefits. The evaluation is done by cost- benefit analysis (CBA) with a dataset of the Korean market while considering operational constraint costs as well as scheduled energy payments, and a simulation algorithm for the evaluation is provided. Our results show the potential for huge profits to be made by cost reduction. We believe that this research can provide a guideline for a utility firm considering investing in ESSs for frequency regulation application as a source of cost reduction