• 한국HCI학회:학술대회논문집
• /
• 2006.02a
• /
• pp.937-944
• /
• 2006

Although people's anxiety about the environmental problem has been getting higher, they are not provided good quality of knowledge about the environment. Based on this situation, Ecoblog can be a new type of online community to educate the public in ecological knowledge. Especially, Ecoblog can be utilized as a method of "preventive education", and it will contribute to reduce great amounts of environmental budget to restore contaminated environment to previous condition. Ecoblog also utilizes the concept of blog which user can create and append their site with chosen themes. A weblog or a blog is a non-commercial webpage regularly updated through the use of a blogging software which allows the user to "publish" kinds of amalgamations of text and graphics to the page as posts. The technology offered in Ecoblog is utilizing the concept of 4D place and game metaphor in order to provide users the sense of participation, interaction and immersion among them and the growing community. Thus, it requires applying the CAAD technology by implementing semantically well-defined building data model as a core database to create a 4D virtual community. This research focuses on defining a 4d spatial framework suitable for developing an online ecological community. Through our study, the state-of-the-art of online community has been studied at the first step. Second, the scenario of using EcoBlog described with content, visualization and navigation are defined based on the critical features derived at the first step. Finally, a 4d spatial framework composed of semantic building data model, content and rule database is constructed to propose factors that are necessary to establish an ecological virtual community. In conclusion, our framework could enhance the comprehension and interaction between users and virtual buildings in the ecological community by integrating the concept of game design, 4D CAD and semantic data model. Such framework can be applied to any online community for an educational purpose.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.9
• /
• pp.33-38
• /
• 2009

The group CSD (GCSD) multiplier was recently proposed based on the variation of canonic signed digit (CSD) encoding and partial product sharing. This multiplier provides an efficient design when the multiplications are performed only with a few predetermined coefficients (e.g., FFT). In many DSP applications such as FFT, the (2W-1)-bit product obtained from W-bit multiplicand and W-bit multiplier is quantized to W-bits by eliminating the (W-1) least-significant bits. This paper presents an error compensation method for a fixed-width GCSD multiplier that receives a W-bit input and produces a W-bit product. To efficiently compensate for the quantization error, the encoded signals from the GCSD multiplier are used for the generation of error compensation bias. By Synopsys simulations, it is shown that the proposed method leads to up to 84% reduction in power consumption and up to 79% reduction in area compared with the fixed-width modified Booth multiplier.

• Journal of Astronomy and Space Sciences
• /
• v.32 no.4
• /
• pp.335-340
• /
• 2015

Using the Total Electron Content (TEC) data from the Global Navigation Service System (GNSS) site in Jeju, operated by the Korea Astronomy and Space Science Institute (geographic location: $33.3^{\circ}N$, $126.5^{\circ}E$; geomagnetic location: $23.6^{\circ}N$) for 2002-2014 in Korea, the results of the statistical analysis of positive and negative ionospheric storms are presented for the first time. In this paper, ionospheric storms are defined as turbulences that exceed 50% of the percentage differential Global Positioning System (GPS) TEC ratio (${\Delta}TEC$) with monthly median GPS TEC. During the period of observations, the total number of positive ionospheric storms (${\Delta}TEC$ > 50%) was 170, which is greater than five times the number of negative ionospheric storms (${\Delta}TEC$ < - 50%) of 33. The numbers of ionospheric storms recorded during solar cycles 23 and 24 were 134 and 69, respectively. Both positive and negative ionospheric storms showed yearly variation with solar activity during solar cycle 23, but during solar cycle 24, the occurrence of negative ionospheric storms did not show any particular trend with solar activity. This result indicates that the ionosphere is actively perturbed during solar cycle 23, whereas it is relatively quiet during solar cycle 24. The monthly variations of the ionospheric storms were not very clear although there seems to be stronger occurrence during solstice than during equinox. We also investigated the variations of GPS positioning accuracy caused by ionospheric storms during November 7-10, 2004. During this storm period, the GPS positioning accuracies from a single frequency receiver are 3.26 m and 2.97 m on November 8 and 10, respectively, which is much worse than the quiet conditions on November 7 and 9 with the accuracy of 1.54 m and 1.69 m, respectively.

• 한국HCI학회:학술대회논문집
• /
• 2008.02a
• /
• pp.326-331
• /
• 2008

We present the seamless browsing - a new Zooming technique based on the zoom ratios and the distances of the hyperlinks from the pointer. In most cases, users have to activate the interesting link after guessing the target content of it, just based on the insufficient information from the link label or title. We propose that a web browser displays a limited number of hyperlinks in an area around the pointer in a distinguished way, e.g. in different sizes of thumbnails, transparency or style. If a user zooms in on the pointer area, to new web browser displays the varying images of hyperlink-targets according to the zoom ratio, and finally it transfers to the new target page which was nearest to the pointer position. This method allows users to easily select a hyperlink based on rich information given by zoomable thumbnails and seamlessly to transit through web pages just with zooming. 1n our experiments, results show that the seamless browsing significantly outperforms the legacy way.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.4
• /
• pp.343-352
• /
• 2016

A multi-rotor vehicle is an unmanned vehicle consisting of multiple rotors. A multi-rotor vehicle can be categorized as tri-, quad-, hexa-, and octo-rotor depending on the number of the rotors. Multi-rotor vehicles have many advantages due to their agile flight capabilities such as the ability for vertical take-off, landing and hovering. Thus, they can be widely used for various applications including surveillance and monitoring in urban areas. Since multi-rotors are subject to uncertain environments and disturbances, it is required to implement robust attitude stabilization and flight control techniques to compensate for this uncertainty. In this research, an advanced nonlinear control algorithm, i.e. sliding mode control, was implemented. Flight experiments were carried out using an onboard flight control computer and various real-time autonomous attitude adjustments. The feasibility and robustness for flying in uncertain environments were also verified through real-time tests based on disturbances to the multi-rotor vehicle.

• International Journal of Highway Engineering
• /
• v.18 no.3
• /
• pp.87-94
• /
• 2016

PURPOSES : This study analyzed the lane-by-lane traffic flow characteristics in Korea by using real-world data, including congestion levels, for 2-, 3-, and 4-lane freeways. METHODS : On the basis of a literature review, lane flow and speed characteristics were analyzed using flow measurements and speed ratios. In addition, the effect of congestion levels on traffic flow were visualized using rescaled cumulative plots. RESULTS : Driver behavior varied depending on the congestion level. During free-flow conditions, the lane-use ratio of individual lanes varied largely, whereas during congestion, the ratio was nearly the same for all lanes (i.e., equilibrium). During maximum-flow and congestion conditions, the median lane was used more than the shoulder lane, whereas during all other conditions, the shoulder lane had a higher lane-use ratio. In 3- or 4-lane freeways, the lane-use ratio of the median lane always exceeded 1 and was the highest during free-flow conditions. CONCLUSIONS : The results of the present analysis can be used as an index to predict congestion before a lane is overcapacitated. Moreover, the results can be applied in variable lane guidance systems, such as car navigation systems and variable message displays, to control traffic flow.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.9
• /
• pp.1993-1998
• /
• 2010

This paper presents an integrated control module for controlling transportation machine and automatic navigation using a combined technology of mobile telematics and transportation machine telematics, i.e. Mobile In Vehicle (MIV). This development includes hardware implementation and its verification of control mechanism applied to vehicle. In particular, the module is designed to be versatile in such a way that it can collect various information and facilitate various options for convenience by supporting existing networks, such as TCP/IP, Wi-Fi and 3G mobile radio networks. The study offers its versatility, intelligence and cost-effectiveness by enabling the module to support network-independent service, whereas conventional modules operate only in a certain network. Based on this module, a multiple of subsequent convenient functions for transportation machine can further be developed for safe and intelligent transportation machines.

• Journal of Institute of Control, Robotics and Systems
• /
• v.21 no.9
• /
• pp.888-897
• /
• 2015

A flight capability to take a terrain following flight near the ground is required to reduce the probability that a fighter aircraft can be detected by foe's radar fence in the battlefield. The success rate for mission flight has increased by adopting TFS (Terrain Following System) to enable the modern advanced fighter to fly safely near the ground at the low altitude. This system has applied to the state-of-the-art fighter and bomber, such as B-1, F-111, F-16 E/F and F-15, since the research begins from 1960's. In this paper, the terrain following system and GCAS (Ground Collision Avoidance System) was developed, based on a digital database with UTAS's TERPRROM (TERrain PROfile Matching) equipment. This system calculates the relative location of the aircraft in the terrain database by using the aircraft status information provided by the radar altimeter and the INS (Inertial Navigation System), based on the digital terrain database loaded previously in the DTC (Data Transfer Cartridge), and figures out terrain features around. And, the system is a manual terrain following system which makes a steering command cue refer to flight path marker, on the HUD (Head Up Display), for vertical acceleration essential for terrain following flight and enables a pilot to follow it. The cue is based on the recognized terrain features and TCH (Target Clearance Height) set by a pilot in advance. The developed terrain following system was verified in the real-time pilot evaluation in FA-50 HQS (Handling Quality Simulator) environment.

• Journal of Information Technology Application
• /
• v.3 no.1
• /
• pp.1-21
• /
• 2001

The explosive growth of the Internet and the increasing popularity of the World Wide Web have generated significant interest in the development of electronic commerce in a global online marketplace. The rapid adoption of the Internet as a commercial medium is rapidly expanding the necessity of Web advertisement as a new communication channel. if proper Web advertisement could be suggested to the right user, then effectiveness of Web advertisement will be raised and it will help company to earn more profit. So, this article describes a personalized advertisement technique as a part of intelligent customer services for an electronic newspaper provide. Based on customers history of navigation on the electronic newspapers pages, which are divided into several sections such as politics, economics, sports, culture, and so on, appropriate advertisements (especially, banner ads) are chosen and displayed with the aid of machine learning techniques, when customers visit to the site. To verify feasibility of the technique, an application will be made to one of the most popular e-newspaper publishing company in Korea.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.5
• /
• pp.508-514
• /
• 2004

A fluxgate magnetic sensor consists of a solenoid excitation coil, pick-up coil, and magnetic core. We presents the effect of magnetic core shape in a micromachined fluxgate sensor. To observe the performance of fluxgate sensor with magnetic core side width and gap, side width of 125 ${\mu}{\textrm}{m}$, 250 ${\mu}{\textrm}{m}$, and 500 ${\mu}{\textrm}{m}$ were designed in a rectangular-ring shaped core and the gaps of 0 ${\mu}{\textrm}{m}$, 50 ${\mu}{\textrm}{m}$, and 100 ${\mu}{\textrm}{m}$ were also fabricated in a racetrack shaped core. The solenoid coils and magnetic core were separated by benzocyclobutane(BCB) which had high insulation and good planarization characters. Copper coil patterns of 10 ${\mu}{\textrm}{m}$ width and 6${\mu}{\textrm}{m}$ thickness were electroplated on Ti(300 $\AA$) / Cu(1500 $\AA$) seed layers. 3 ${\mu}{\textrm}{m}$ thick N $i_{0.8}$F $e_{0.2.}$(permalloy) film for the magnetic core was also electroplated under 2000 gauss to induce the magnetic anisotropy. The magnetic core had the high DC effective permeability of ∼1,300 and coercive field of ∼0.1 Oe. Because the magnetic cores of 500 ${\mu}{\textrm}{m}$ side width and 0 gap had a low magnetic flux leakage, high sensitivity of ∼350 V/T were measured at excitation condition of 3 $V_{P-P}$ and 2 MHz square wave. The power consumption of ∼14 ㎽ was measured. The fabricated fluxgate sensor had the very small actual size of 3.0${\times}$1.7 $\textrm{mm}^2$. When two fluxgates were perpendicularly aligned in terrestrial field, their two-axis output signals were very useful to commercialize an electronic azimuth compass for the portable navigation system.m.m.m.