• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.1
• /
• pp.1-7
• /
• 2007

Generally, an electric railroad feeding system has many problems due to the different characteristics in contrast with a load of general three-phase AC electric power system. One of them is harmonics problem caused by the switching device existing in the feeding system, and moreover, the time-varying dynamic loads of rail way is inherently another cause to increase this harmonics problem. In Korea power systems, the electric railroad feeding system is directly supplied from the substation of KEPCO. Therefore, if voltages fluctuation or unbalanced voltages are created by the voltage and current distortion or voltage drop during operation, it affects directly the source of supply. The trainloads of electric railway system have non-periodic but iterative harmonic characteristics as operating condition, because the electric characteristic of the electric railroad feeding system is changed by physical conditions of the each trainload. According to the traditional study, the estimation of harmonics has been performed by deterministic way using the steady state data at the specific time. This method is easy to analyze harmonics, but it has limits in some cases which needs an assessment of dynamic load and reliability. Therefore, this paper proposes the probabilistic estimation method, moments matching method(MW) in order to overcome the drawback of deterministic method. In this paper, distributions for each harmonics are convolved to obtain the moments and cumulants of TDD(Total Demand Distortion), and this can be generalized for any number of trains. For the case study, the electric railway system of LAT(Intra Airport Transit) in Incheon International Airport is modeled using PSCAD/EMTDC dynamic simulator. The raw data of harmonics for the moments matching method is acquired from simulation of the LAT model.

• Smart Structures and Systems
• /
• v.22 no.1
• /
• pp.81-94
• /
• 2018

Automatic Generation Control (AGC) has functionally controlled the interchange power flow in order to suppress the dynamic oscillations of frequency and tie-line power deviations as a perturbation occurs in the interconnected multi-area power system. Furthermore, Flexible AC Transmission Systems (FACTS) can effectively assist AGC to more enhance the dynamic stability of power system. So, Static Synchronous Series Compensator (SSSC), one of the well-known FACTS devices, is here applied to accurately control and regulate the load frequency of multi-area multi-source interconnected power system. The research and efforts made in this regard have caused to introduce the Fractional Order Proportional Integral Derivative (FOPID) based SSSC, to alleviate both the most significant issues in multi-area interconnected power systems i.e., frequency and tie-line power deviations. Due to multi-objective nature of aforementioned problem, suppression of the frequency and tie-line power deviations is formularized in the form of a multi-object problem. Considering the high performance of Multi Objective Bees Algorithm (MOBA) in solution of the non-linear objectives, it has been utilized to appropriately unravel the optimization problem. To verify and validate the dynamic performance of self-defined FOPID-SSSC, it has been thoroughly evaluated in three different multi-area interconnected power systems. Meanwhile, the dynamic performance of FOPID-SSSC has been accurately compared with a conventional controller based SSSC while the power systems are affected by different Step Load Perturbations (SLPs). Eventually, the simulation results of all three power systems have transparently demonstrated the dynamic performance of FOPID-SSSC to significantly suppress the frequency and tie-line power deviations as compared to conventional controller based SSSC.

• The Journal of the Korea Contents Association
• /
• v.17 no.11
• /
• pp.9-17
• /
• 2017

In this paper, we propose a method to develop a multimeter which is used for measuring electric signals in industrial field by using battery and display of smart phone. Most of the multimeters that are linked to existing smartphones are connected to Bluetooth, which is inconvenient for battery use and low in measurement accuracy. To improve this, we developed smart multimeter that can supply power and data at the same time by USB OTG method which can be used by sharing the power of smartphone. We also developed a smart multimeter that can measure resistance, DC voltage, current, AC voltage and current. Developed an Android app with a button that displays measurement data and can select the type of electric signal to be measured, and tests whether the manufactured system is operating normally or not. Respectively.The results of this study confirm that it is possible to fabricate a smart meter that has equal or better performance compared to existing instruments and does not require a separate power source or display, and it is expected to be a reference for the development of various smart instruments in the future.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.6
• /
• pp.49-57
• /
• 2015

This paper presents the discharge characteristics and economic feasibility of a Dry $Air/O_2$ and a $N_2/O_2$ mixture gas in order to review $SF_6$ alternative. From AC discharge experiment in an quasi-uniform field, it was found that the optimal $N_2/O_2$ mixing ratio which breakdown voltage and surface flashover voltage were the highest was 70/30 and that the pressure dependence on the breakdown voltage was higher than that of the surface flashover voltage in the Dry $Air/O_2$ and the $N_2/O_2$ mixture gas. The mixing ratio (70/30) and the tendency of the pressure dependence were described in detail based on physical factors (impact ionization coefficient, electron attachment coefficient, secondary electron emission coefficient) involved in discharge mechanism and a electron source, respectively. In addition, the performance insulation and the economic feasibility of the Dry $Air/O_2$ and the $N_2/O_2$ mixture gas were discussed so that Dry $Air/O_2$ mixture gaswas more suitable than $N_2/O_2$ mixture gas to the $SF_6$ alternative.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.21
• /
• pp.9241-9247
• /
• 2014

Background: Rs31489 in the cleft lip and palate transmembrane1-like gene (CLPTM1L) has been identified to be associated with lung cancer through genome-wide association studies (GWAS). However, some recent replication studies yielded inconclusive results. Thus, we undertook this study to investigate the precise effect of rs31489 on lung cancer susceptibility. Materials and Methods: A hospital-based case-control study in 1,673 Chinese subjects (611 individuals with lung cancer and 1,062 controls) and a meta-analysis among 32,199 subjects (16,364 cases and 15,835 controls) were performed in this study. Results: In our case-control study, rs31489 was inversely associated with lung cancer (AC versus CC: OR=0.68, 95%CI=0.52-0.88; additive model: OR=0.68, 95%CI=0.54-0.85; dominant model: OR=0.65, 95%CI =0.51-0.84). Stratification analysis by smoking status showed a significant association and strong genetic effect in non-smokers but not in smokers. Our meta-analysis further confirmed the association, although with significant heterogeneity contributed by study design and source of controls, as shown by stratified analysis. Sensitive and cumulative analyses both indicated robust stability of our results. In addition, there was no observable publication bias in our meta-analysis. Conclusions: Overall, the findings from our replication study and meta-analysis demonstrated that CLPTM1L gene rs31489 is significantly associated with lung cancer.

• Proceedings of the KIEE Conference
• /
• 1998.07d
• /
• pp.1370-1372
• /
• 1998

Boron doped CdS films were prepared by CBD(Chemical Bath Deposition) method using boric acid ($B_3HO_3$) as donor dopant source, and their properties were investigated. As-grown CdS films were highly adherent and specularly reflective. Boron doped CdS film which was fabricated under the condition of 0.01 $B_3HO_3/Cd(Ac)_2$ mole ratio, exhibited the lowest resistivity of $2{\Omega}cm$ and the highest optical bandgap of 2.41eV. Also, CdS/CdTe solar cells were fabricated with various doping concentration of CdS films. Using optimized CdS film as the window layer of CdS/CdTe solar cell, the characteristics of the cell were improved. ( $V_{oc}$=610mV, $J_{sc}$=37.5mA/cm, FF=0.4, $\eta$=9.1% )

• Journal of the Korean Society of Costume
• /
• v.31
• /
• pp.189-202
• /
• 1997

Movie is one of the most popular culture ac-tivities in modern society and the composite rt of science and art born in the 20th century. Movie became the great source of setting the fashion. Especially movie costume brought into relief and was accepted by the mass. As a movie stimulates imitation psychology and identification of the general public in fashion. The purpose of this study is to analyze the effects of the movie costume to a modern mass fashion. The times was defined the movies from the early Silent era to the modern Hollywood movie from the late of 1910 to 1990. The way of study were to analyze on the changes and roles of movie costume through documentary records and the influence of set-ting the fashion to the mass fashion and classi-fied it five times-silent era classics neo-classics new look and modern times. The summary of result is as follows, 1, Movie costume affected the dress and the fashion of women is Silent era. That fashion was accelerated by actors' costumes in the mode of 1920. 2. Holloywood movies in the Classics show the essence of the fashion movie costume played a role of a fashion leader and commanded the trend of mass fashion. 3. Practical style was shown because of the war in the Neo-classics. Movie industry was prosperous after the war. But the consequences of the movie costume to the mass fashion were more and more weaken 4. Couture designer's costume had an effect on the mass fashion in the early of New look. But it was behind the fashion for the rise of young fashion. 5. The tastes of the fashion were diversified in Modern times. So the movie fashion was not imitated or popular. The costume of "Pret-a-porter" was used in the movies in the 1980. Spectators became to wear the same style of the actors. The times fashion and movie interacted each other. Movie costume is playing a role of a fashion leader guiding the mass fashion.s fashion.

• Journal of the Korean Society of Costume
• /
• v.34
• /
• pp.109-120
• /
• 1997

The conservation of collections in muse-ums is an important aspect for our her-itage. The control of museum environment is a vital factor in the preservation of cool-lections. Inappropriate or fluctuating envi-ronmental conditions can cause irreparable damage to works of arts. In this research we investigated the ac-tual conditions of museum environment for old testiles using questionnaire and mea-sured dye fasing of old textiles on exhibi-tion for 2 months in a university museum the major results are as follows: 1. The control of temperature and rela-tive humidity is a vital factors I the preservation of old textiles in museum generally acceptable temperature and rel-ative humidity standards for old textiles are 18-23$^{\circ}C$ and 50-65% R. H and light level for textiles on exhibition should be limited to 30-50 lux. 2, In university museums the limate control system in exhibition and storage area is in an early stage. Therefore to minimize the deterioration of old textiles the best method of controlling the envi-ronment is to have centralized climate control system in sorage area as well as in display area. 3. Conservator is needed to maintain collections scientifically. Only professional conservator by combining scientific tech-nical and artistic training has the exper-tise needed to maintain the physical in-tegrity of old textiles. In order to solve the inferior environment of museums the staff should recognize the importance of the condition of exhibition and storage. 4. Old textiles are susceptible to damage by light and associated heat. Dyed textiles which have been exhibited under the light without any UV filter were faded notice-ably within two months of exhibition. Light levels for textiles on exhibition should be limited to 30-50 lux. It is de-sirable to use special light source that can absorb UV. and UV filter is also recom-mended to reduce photodegradation of old textiles.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1678-1683
• /
• 2003

DBD(Dielectric Barrier Discharge) plasma in air is well established for the production of large quantities of ozone and is more recently being applied to aftertreatment processes for HAPs(Hazardous Air Pollutants). Although DBD high electron density and energy, its potential use as nano and sub-micron sized particle charging are not well known. Aim of this work is to determine design and operating parameters of a two-stage ESP with DBD. DBD and ESP are used as particle charger and precipitator, respectively. We measured particle precipitation efficiency of two-stage ESP and estimated ozone decomposition of both pelletized $MnO_2$ catalyst and pelletized activated carbon. To examine the particle precipitation efficiency, nano and sub-micron sized particles were generated by a tube furnace and an atomizer. AC voltage of $7{\sim}10$ kV(rms) and 60 Hz is used as DBD plasma source. DC -8 kV is applied to the ESP for particle precipitation. The overall particle collection efficiency for the two-stage ESP with DBD is over 85 % under 0.64 m/s face velocity. Ozone decomposition efficiency with pelletized $MnO_2$ catalyst or pelletized activated carbon packed bed is over 90 % when the face velocity is under 0.4 m/s in dry air.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2002.09a
• /
• pp.474-477
• /
• 2002

Equipment to cauterize tumors by an electrically heated Kanthal wire is under development. The wire( alloy of iron, chromium and Aluminum) keeps sufficient strength up to 1400 degrees in Celsius. Although AC 50Hz current source is used in the prototype experiment, RF current will be used in future. The diameter of the Kanthal wire was 0.3 mm which was connected to Kanthal wire of 0.8 mm. The thicker wire was used as a leading wire. The possibility of application of the heating wire in combination with an ultrasound endoscope was determined, where ultrasound endoscope is to be used to monitor the location on the wire and an extent of a tumor in digestive organs. This procedure requires the wire to be applied inside ultrasound transmitting media. First, the wire was applied in the degassed water in which a chicken liver sample was submerged. The wire, however, burned out in water soon after it became red-hot at 12 A. The reason is that large current is required for the wire to become red-hot due to strong convection. Starch paste of 3 weight percent was employed instead of water. This made the wire red-hot approximately at 6 A, showing the increased viscosity of the starch decreased the convection and the wire was cover by the steam. The liver sample was cauterized successively, while the location of the wire and the liver was monitored by an ultrasound diagnosis equipment outside the plastic vessel of the starch paste.