• Journal of the Korean Society of Industry Convergence
• /
• v.27 no.2_1
• /
• pp.297-306
• /
• 2024

This study identified the power distance tendency of firefighters. Power distance propensity is one of the important organizational and cultural factors that influence the development of the organization. There is a big difference in the attitude of the members of the organization to perform their work according to the tendency of the distance of power. As a result of the main study, the overall level of power distance propensity of the subjects was 2.55 points on average. In particular, there was a significant difference in the propensity of power distance according to class (p<0.05). In the future, it is necessary to study the effect of job characteristics according to the rank of firefighters on the propensity to distance power. It is expected to form a positive organizational culture of the firefighting organization by utilizing the power distance tendency of the members of the organization.

• Communications for Statistical Applications and Methods
• /
• v.27 no.6
• /
• pp.589-602
• /
• 2020

The development of smart grids has enabled the easy collection of a large amount of power data. There are some common patterns that make it useful to cluster power consumption patterns when analyzing s power big data. In this paper, clustering analysis is based on distance functions for time series and clustering algorithms to discover patterns for power consumption data. In clustering, we use 10 distance measures to find the clusters that consider the characteristics of time series data. A simulation study is done to compare the distance measures for clustering. Cluster validity measures are also calculated and compared such as error rate, similarity index, Dunn index and silhouette values. Real power consumption data are used for clustering, with five distance measures whose performances are better than others in the simulation.

• Journal of the Korean Society of Industry Convergence
• /
• v.27 no.3
• /
• pp.645-653
• /
• 2024

This study is a comparative study on the tendency of power distance between administrative and field personnel in fire departments. For this study, 355 firefighters nationwide were surveyed from August 22 to December 31, 2023, and the collected data was analyzed using the SPSS 24.0 statistical program. As a result of the reliability analysis, Cronbach's =.803 was found to be higher than the standard value of 0.6. irefighting agencies are firefighting organizations that work to resolve incidents quickly and efficiently at disaster sites, and an appropriate level of power distance is essential. However, excessive power distance between superiors and subordinates leads to self-righteousness in administration and incompetence in field activities through one-sided instructions and compliance. As a result of analyzing the power distance tendencies of administrative and field workers in fire departments in this study, it was confirmed that there was no bias in either direction with an average score of 2.55. And the level of power distance tendency between administrative and field firefighters was 2.56 points, showing no significant difference.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.50 no.9
• /
• pp.411-416
• /
• 2001

Distance relay is the most widely used in transmission line protection because it is applicable not only as main protection but also as back-up protection. However, the protection range of the distance relay is always fixed in the unchangeable operating range while the power system varies, and therefore the distance relay is the device that is the highly influenced by the power system changes. In this regard, this paper describes an approach to minimize the mal-operation of the distance relay due to the power system changes through changing protection range of the distance relay into optimal condition in response to the load variation and power system condition. Also mal-function of the distance repay in case of high resistance ground faults could be minimized through modeling the protection range into quadratic function.

• Journal of Information Processing Systems
• /
• v.16 no.5
• /
• pp.1158-1168
• /
• 2020

The distance vector-hop wireless sensor node location method is one of typical range-free location methods. In distance vector-hop location method, if a wireless node A can directly communicate with wireless sensor network nodes B and C at its communication range, the hop count from wireless sensor nodes A to B is considered to be the same as that form wireless sensor nodes A to C. However, the real distance between wireless sensor nodes A and B may be dissimilar to that between wireless sensor nodes A and C. Therefore, there may be a discrepancy between the real distance and the estimated hop count distance, and this will affect wireless sensor node location error of distance vector-hop method. To overcome this problem, it proposes a wireless sensor network node location method by modifying the method of distance estimation in the distance vector-hop method. Firstly, we set three different communication powers for each node. Different hop counts correspond to different communication powers; and so this makes the corresponding relationship between the real distance and hop count more accurate, and also reduces the distance error between the real and estimated distance in wireless sensor network. Secondly, distance difference between the estimated distance between wireless sensor network anchor nodes and their corresponding real distance is computed. The average value of distance errors that is computed in the second step is used to modify the estimated distance from the wireless sensor network anchor node to the unknown sensor node. The improved node location method has smaller node location error than the distance vector-hop algorithm and other improved location methods, which is proved by simulations.

• Journal of Electrical Engineering and Technology
• /
• v.13 no.5
• /
• pp.1831-1840
• /
• 2018

During a power swing, distance relays may mistakenly spread fault throughout the power grid, causing a great deal of damage. In some cases, such mistakes can cause global outages. For this reason, it is critical to make a distinction between power swings and faults in distance relays. In this paper, a new method is proposed based on RMS measurement to differentiate between faults and power swings. The proposed method was tested on two standard grids, demonstrating its capability in detecting a power swing and simultaneous fault with power swing. This method required no specific configurations, and was independent of grid type and zoning type of distance relays. This feature in practice allows the relay to be installed on any grid with any kind of coordination. In protective relays, the calculations applied to the microprocessor is of great importance. Distance relays are constantly calculating the current RMS values for protection purposes. This mitigates the computations in the microprocessor to detect power swings. The proposed method was able to differentiate between a fault and a power swing. Furthermore, it managed to detect faults occurring simultaneously with power swings.

• KIEE International Transactions on Power Engineering
• /
• v.4A no.1
• /
• pp.26-32
• /
• 2004

Digital technology has advanced significantly over the years both in terms of software tools and hardware availability. It is now applied extensively throughout many area of electrical engineering including protective relaying in power systems. Digital relays have numerous advantages over traditional analog relays, such as the ability to accomplish what is difficult or impossible using analog relays. Although non real-time simulators like PSCAD/EMTDC are employed to test the algorithms, such simulations are disadvantaged in that they cannot test the relay dynamically. Hence, real-time simulators like RTDS are used. However, the latter requires large space and is very expensive. This paper uses EMTP MODELS to simulate the power system and the distance relay. The distance relay algorithm is implemented and the distance relay is interfaced with a test power system. The distance relay's performance is then assessed interactively under various fault types, fault distances and fault inception angles. The test results show that we can simulate the distance relay effectively and we can examine the operation of the distance relay very closely including its drawbacks/limitations by using EMTP MODELS. Equally important, this approach facilitates any changes that need to be carried out in order to enhance the Distance Relay under test/examination.

• Communications for Statistical Applications and Methods
• /
• v.16 no.6
• /
• pp.989-995
• /
• 2009

Basu et al. (1998) proposed the minimum divergence estimating method which is free from using the painful kernel density estimator. Their proposed class of density power divergences is indexed by a single parameter $\alpha$ which controls the trade-off between robustness and efficiency. In this article, (1) we introduce a new large class the minimum squared distance which includes from the minimum Hellinger distance to the minimum $L_2$ distance. We also show that under certain conditions both the minimum density power divergence estimator(MDPDE) and the minimum squared distance estimator(MSDE) are asymptotically equivalent and (2) in finite samples the MDPDE performs better than the MSDE in general but there are some cases where the MSDE performs better than the MDPDE when estimating a location parameter or a proportion of mixed distributions.

• Proceedings of the KIEE Conference
• /
• 2001.05a
• /
• pp.290-293
• /
• 2001

This paper presents the reach accuracy of a distance relay for protection of transmission line according to power system conditions. The apparent impedance of distance relay is considerably affected by source impedance, load current, power factor, fault point and resistance etc. For protective coordination on the variables power system parameters, trip characteristics of distance relay at sending and receiving terminal are discussed.

• Journal of the Korean Society for Heat Treatment
• /
• v.3 no.1
• /
• pp.1-7
• /
• 1990

To investigate the influence of r.f. power and electrode distance on the TiN deposition, TiN films were deposited onto STC3, STD11 steel and Si-wafer from gas mixtures of $TiC_4/N_2/H_2$ using the radio frequency plasma assisted chemical vapor deposition. The crystallinity of TiN film could be improved by the increase of r.f. power and the decrease of electrode distance. The TiN coated layer contains chlorine, its content were decreased with increasing r.f. power as well as decreasing electrode distance. And the thickness of deposited TiN was largely affected by r.f. power and electrode distance. The hardness of deposited TiN reached a maximum value of about Hv 2,000.