• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.36 no.11
• /
• pp.1119-1126
• /
• 2012

The collective behavior of bacteria plays an important role in biofilm development. In this study, the fluidic properties of biofilms formed in Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) colonies were compared by visualizing 200-nm fluorescent beads that were initially embedded in an agar plate and distributed spontaneously on the upper surface of the growing colonies. We conducted experiments to measure the three-dimensional profile of the E. coli colony using fluorescent microbeads that did not flow in the colony. Vortical flow patterns near the edge of the B. subtilis colony were observed clearly by tracking the movement of the beads in the biofilm of the colony. The present study should be the first step toward determining the effect of fluidic biofilms on the growth and swarming dynamics of bacteria.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.3
• /
• pp.1213-1222
• /
• 2011

The aim of this research is to map the intellectual structure of the field of LED and optics during the period of 2000-2009. We utilize the scientometric tool of co-word analysis to reveal patterns and trends in the LED and optics field by measuring the association strengths of keywords (or IPCs). Data were collected from Science Citation Index Expanded (SCIE) and United Stated Patent and Trademark Office (USTPO) for the period of 2000-2009. Keywords were extracted from abstracts and further standardized using thesaurus. In order to trace the dynamic changes of the LED and optics field, the whole 10-year period was separated into two consecutive periods: 2000-2004 and 2005-2009. The results show that the LED and optics field has some established research themes and it also changes to embrace new themes.

• Journal of the Korean Society of Radiology
• /
• v.8 no.2
• /
• pp.51-56
• /
• 2014

We analyzed how insole affects the dynamic stability and the balance while a body moves or stops. Specially we've sorted out variations of individual balance ability while we make a longitudinal arch stop artificially as a usual situation(just standing and putting one's weight). We found ten men and girls each with suitable feet for our experimentation as the subject of investigation and made individual insole for them by measuring medial longitudinal arch. Then we compared before and after movement of the power point of application and a pattern of COP using the Tetrax balance equipment. We found out it is better for balance ability when we wear insoles. It turned out to be helpful for increasing balance ability of body to use insole which supports medial longitudinal arch of longitudinal arch well.

• Environmental and Resource Economics Review
• /
• v.22 no.2
• /
• pp.251-279
• /
• 2013

Prices of oil products such as gasoline and diesel are deregulated since 1997 while electricity price is still controlled by government. This difference may explain recent discrepancy in the patterns of demand for oil products and electricity - constant increase in electricity consumption and stagnant demand for oil. To verify it empirically, we estimate price and income (production) elasticity of demand across time by using a rolling regression with 10 year-window based on monthly data for 1981-2011. Estimation results show that the sensitivity to price in demand for gasoline and diesel has increased since mid-90s while the elasticity of demand for electricity has become smaller. Second, income (production) elasticities of demand have shown no significant changes for both oil products and electricity. Third, cross-price elasticity was found meaningful only for gasoline before mid 1990s and for diesel after then.

• The Journal of the Korea Contents Association
• /
• v.10 no.8
• /
• pp.104-110
• /
• 2010

In the field of biotechnology, computer can play varied roles such as the ordinal analysis, ordianl comparison, nutation tracing, analogy comparison for drug design, estimation of protein function, cell mechanism, and verifying the role of a gene for preventing diseases. Additionally, by constructing database, it can provide an application for the cloning process in other data researches, and be used as a basis for the comparative genetics. For the most of researcher about biotechnology, they need to use the tool that can do all of job above. This study is focused on looking into problems of existing systems to analysis bio data, and designing an improved analyzing system that can propose a solution. In additional, it has been considered to improve the performance of each constituent, and all the constituents, which have been separately processed, are combind in a single system to get over old problems of the existing system.

• The Journal of the Korea Contents Association
• /
• v.8 no.6
• /
• pp.54-65
• /
• 2008

When DDoS attack is achieved, malicious host discovering is more difficult on wireless network than existing wired network environment. Specially, because wireless network is weak on wireless user authentication attack and packet spoofing attack, advanced technology should be studied in reply. Integrated Access Device (IAD) that support VoIP communication facility etc with wireless routing function recently is developed and is distributed widely. IAD is alternating facility that is offered in existent AP. Therefore, advanced traffic classification function and real time attack detection function should be offered in IAD on wireless network environment. System that is presented in this research collects client information of wireless network that connect to IAD using AirSensor. And proposed mechanism also offers function that collects the wireless client's attack packet to monitoring its legality. Also the proposed mechanism classifies and detect the attack packet with W-TMS system that was received to IAD. As a result, it was possible for us to use IAD on wireless network service stably.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.6
• /
• pp.96-101
• /
• 2003

Korea Sounding Rocket(KSR)-III onboard telemetry system has acquired various data from subsystems and sensors in the rocket, and radiated PCM/FM data using two S-band antennas during the flight. Simultaneously， it is necessary that the ground receiving systems track the rocket, and receive and decode telemetry data. Also post processed telemetry data are needed to be broadcasted on ethernet network in real time. Range safety display system displays flight trajectory using telemetry data in mission control center, and so flight manager makes a decision for flight termination from the trajectory This paper describes operating technique about telemetry reception, the development for the realtime data processing system, and the results for telemetering reception on fight test. We telemetered, processed, and broadcasted numerous telemetry data during the flight test successfully.

• Journal of Korean Library and Information Science Society
• /
• v.43 no.1
• /
• pp.221-239
• /
• 2012

The information that has been created according to the complex environment and usage pattern of library user can provide context-aware information service through knowledge structuralization on whether it is a suitable situation for user. Accordingly, the development of a context model for defining the various contexts of library user and for the structuralization of interrelated context information is an essential requirement. This study examined the context concept and context modeling, and utilizing the concept of Activity Theory by Engestrom, the activity model of library user was designed as 1) subject, 2) object, 3) tools, 4) divison of labor, 5) community, and 6) rules. In addition, for the purpose of analyzing the context of library user, activity information was tracked to utilize the Shadow Tracking for observing and recording their forms, and the methodology of CAbAT (Context Analysis based on Activity Theory) was utilized for the collected activity information to analyze the user context model.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.9A
• /
• pp.694-701
• /
• 2003

In this paper, we present a hardware structure and new features of a smart antenna BTS (Base Transceiver Station) for CDMA2000 1X system. The proposed smart antenna BTS is a composite system consisting of many subsystems, i.e., array antenna element, frequency up/down converters, AD (Analog-to-Digital) and DA (Digital-to-Analog) converters, spreading/despreading units, convolutional encoder/Viterbi decoder, searcher, tracker, beamformer, calibration unit etc. Through the experimental tests, we found that the desired beam-pattern in both uplink and downlink communications is provided through the calibration procedure. Also it has been confirmed that the adaptive beamforming algorithm adopted to our smart antenna BTS is fast and accurate enough to support 4 fingers to each user. In our experiments, commercial mobile terminals operating PCS (Personal Communication System) band have been used. It has been confirmed that the smart antenna BTS tremendously improves the FER (Frame Error Rate) performance compared to the conventional 2-antenna diversity system.

• Journal of KIISE:Computing Practices and Letters
• /
• v.15 no.3
• /
• pp.145-153
• /
• 2009

Trajectory data are ubiquitous in the real world. Recent progress on satellite, sensor, RFID, video, and wireless technologies has made it possible to systematically track object movements and collect huge amounts of trajectory data. Accordingly, there is an ever-increasing interest in performing data analysis over trajectory data. In this paper, we develop a data mining tool for massive trajectory data. This mining tool supports three operations, clustering, classification, and outlier detection, which are the most widely used ones. Trajectory clustering discovers common movement patterns, trajectory classification predicts the class labels of moving objects based on their trajectories, and trajectory outlier detection finds trajectories that are grossly different from or inconsistent with the remaining set of trajectories. The primary advantage of the mining tool is to take advantage of the information of partial trajectories in the process of data mining. The effectiveness of the mining tool is shown using various real trajectory data sets. We believe that we have provided practical software for trajectory data mining which can be used in many real applications.