• Environmental Engineering Research
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• 제25권3호
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• pp.366-373
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• 2020

The autonomous vehicles (AVs) could make a positive or negative impact on reducing mobile emissions. This study investigated the changes of mobile emissions that could be caused by large-scale adoption of AVs. The factors of road capacity increase and speed limit increase impacts were simulated using a conceptual modeling approach that combines a hypothetical speed-emission function and a traffic demand model using a virtual transportation network. The simulation results show that road capacity increase impact is significant in decreasing mobile emissions until the market share of AVs is less than 80%. If the road capacity increases by 100%, the mobile emissions will decrease by about 30%. On the other hand, driving speed limit increase impact is significant in increasing mobile emissions, and the environmentally desirable speed limit was found at around 95 km/h. If the speed limit increases to 140 km/h, the mobile emissions will increase by about 25%. This is because some vehicles begin to bypass the congested routes at high speeds as speed limit increases. Based on the simulation results, it is clear that the vehicle platooning technology implemented at reasonable speed limit is one of the AV technologies that are encouraging from the environmental point of view.

• 대한원격탐사학회지
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• 제22권3호
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• pp.221-228
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• 2006

In this study, an integrated 3D modeling and rendering system dealing with 3D urban landscape features such as terrain, building, road and user-defined geometric ones was designed and implemented using $OPENGL\;{|}\;ES$ (Embedded System) API for mobile devices of PDA. In this system, the authoring functions are composed of several parts handling urban landscape features: vertex-based geometry modeling, editing and manipulating 3D landscape objects, generating geometrically complex type features with attributes for 3D objects, and texture mapping of complex types using image library. It is a kind of feature-based system, linked with 3D geo-based spatial feature attributes. As for the rendering process, some functions are provided: optimizing of integrated multiple 3D landscape objects, and rendering of texture-mapped 3D landscape objects. By the active-synchronized process among desktop system, OPENGL-based 3D visualization system, and mobile system, it is possible to transfer and disseminate 3D feature models through both systems. In this mobile 3D urban processing system, the main graphical user interface and core components is implemented under EVC 4.0 MFC and tested at PDA running on windows mobile and Pocket Pc. It is expected that the mobile 3D geo-spatial information systems supporting registration, modeling, and rendering functions can be effectively utilized for real time 3D urban planning and 3D mobile mapping on the site.

• 제어로봇시스템학회논문지
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• 제16권3호
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• pp.239-244
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• 2010

This paper is to present map building of mobile robot using RFID (Radio Frequency Identification) technology and ultrasonic sensor. For mobile robot to perform map building, the mobile robot needs its localization and accurate driving in space. In this reason, firstly, kinematic modeling of mobile robot under non-holonomic constrains is introduced. Secondly, based on this modeling, a tracking controller is designed for tracking a given path based on backstepping method using Lyapunov function. The Lyapunov function is also introduced for proving the stability of the designed tracking controller. Thirdly, 2D map building is performed by RFID system, mobile robot system and ultrasonic sensors. The RFID mobile robot system is composed of DC motor, encoder, ultra sonic sensor, digital compass, RFID receiver and RFID antenna. Finally, the path tracking simulation results and map building experimental results are presented to show the effectiveness of the designed controller.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제23권1호
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• pp.13-27
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• 2017

본 논문에서는 사용자 인터페이스(UI) 모델로부터 모바일 웹앱을 자동으로 생성하는 도구를 제시한다. UI 모델은 UI 중심적인 내장형 시스템을 UI 모델링을 통해 효율적으로 개발하기 위한 방법인 PELUM(Pattern and Event based Logical UI Modeling)을 기반으로 한다. 본 논문에서 제시하는 도구는 모델 편집기와 코드 생성기로 이루어져 있다. 모델 편집기는 웹 상에서 논리적 UI 모델(LUM)과 프로그래밍 인터페이스 모델(PIM)을 모델링하는 환경을 제공한다. 코드 생성기는 LUM을 기반으로 앱의 화면구성 및 이벤트 동작을 설정하고 PIM을 기반으로 로컬 데이터베이스 스키마를 자동으로 구성하여 모바일 웹앱을 생성한다. 또한 PIM에서 외부 혹은 open API 주소를 입력 받아 매쉬업 웹앱을 생성하는 기능도 제공한다. 생성된 모바일 웹앱은 사용자가 손쉽게 최적화할 수 있도록 Model-View-Controller(MVC) 아키텍처로 구현하였다. 이를 통해 사용자는 웹 상에서 UI를 모델링하여 여러 기기에서 동작 가능한 모바일 웹앱을 생성할 수 있다.

• 전자공학회논문지B
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• 제33B권4호
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• pp.1-10
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• 1996

In this paper are presented kinematic and dynamic modeling and path-tracking of fourwhelled mobile robot with 2 d.o.f. having the limited drivetorques. Controllability of wheeled-mobile robot is revealed by using the kinematic model. Instantaneously coincident coordinate cystem, force/torques generated by inverse dynamics exceed the limitation, we make wheeled-mobile robot follow the reference path by modifying the planned reference trajectory with time-scaling. The controller is introduced to compensate for error owing to modeling uncertainty and measurement noise. And simulation results prove that method proposed by this paper is efficient.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.59-59
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• 2000

In this paper, we present a framework for modeling and control of multiple mobile robots which cowork within a bounded workspace and limited resources. To achieve this goal, we adopt a formalism of discrete event system and supervisory control theory based on Petri nets. We can divide our whole story into two parts: first, we search the shortest path using the distance vector algorithm, and then we construct the control scheme from which a number of mobile robots can work within a bounded workspace without any collision. The use of Petri net modeling allows us In synthesize a controller which achieves a control specification for the desired closed-loop behavior efficiently. Finally, the usefulness of the proposed Petri net formalism is illustrated by a simulation study.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권8호
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• pp.482-491
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• 2003

In this paper are presented kinematic and dynamic modeling and path-tracking of four-wheeled mobile robots with 2 d.o.f haying the limited drive-torques. Controllability of wheeled-mobile robots is revealed by the kinematic model. Instantaneously coincident coordinate system, force/torque propagation and Newton's equilibrium law are used to drive the dynamic model. When drive-torques generated by inverse dynamics exceed the limitation, we make wheeled-mobile robots follow the reference path by modifying the planned reference trajectory with time-scaling. The controller is introduced to compensate for error owing to modeling uncertainty and measurement noise. And simulation results prove that method proposed by this paper is efficient.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2001년도 The Seoul International Simulation Conference
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• pp.136-140
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• 2001

The 3rd generation mobile telecommunication fields are being standardized and developed in two parts, 3GPP and 3GPP2. These two parts have established each Network Architecture Models to achieve the goals basically required in the 3rd generation and to make it progress to IP network in the future. To achieve these goals many system architectures are proposed. Not only functional aspects but also performance aspects are considered as major factors. This paper proposes a new method of performance evaluation modeling and simulation that improved the existing way. The method proposed in this paper is Aspect oriented logical performance analysis Modeling and Simulation method. This proposed method is expected to improve efficiency of performance analysis modeling and simulation on the 3rd generation mobile telecommunication system.

• 한국IT서비스학회지
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• 제15권2호
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• pp.169-184
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• 2016

Smartphone use is rapidly spreading due to the advantage of being able to connect to the Internet anytime, anywhere--and mobile app development is developing accordingly. The characteristic of the mobile app market is the ability to launch one's app into foreign markets with ease as long as the platform is the same. However, a large amount of prior research asserts that consumers behave differently depending on their culture and, from this perspective, various studies comparing the differences between consumer behaviors in different countries exist. Accordingly, this research, which uses online product reviews (OPRs) in order to analyze the cultural differences in consumer behavior comparatively by nationality, proposes to compare the U.S. and South Korea by selecting ten apps which were released in both countries in order to perform a sentimental analysis on the basis of star ratings and, based on those ratings, to interpret the sentiments in reviews. This research was carried out to determine whether, on the basis of ratings analysis, analysis of review contents for sentiment differences, analysis of LDA topic modeling, and co-occurrence analysis, actual differences in online reviews in South Korea and the U.S. exist due to cultural differences. The results confirm that the sentiments of reviews for both countries appear to be more negative than those of star ratings. Furthermore, while no great differences in high-raking review topics between the U.S. and South Korea were revealed through topic modeling and co-occurrence analyses, numerous differences in sentiment appeared-confirming that Koreans evaluated the mobile apps' specialized functions, while Americans evaluated the mobile apps in their entirety. This research reveals that differences in sentiments regarding mobile app reviews due to cultural differences between Koreans and Americans can be seen through sentiment analysis and topic modeling, and, through co-occurrence analysis, that they were able to examine trends in review-writing for each country.

• 한국콘텐츠학회논문지
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• 제18권5호
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• pp.376-385
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• 2018

본 연구는 3차원 멀티미디어를 활용한 모바일 과제정보 제시가 치아카빙지식, 수행 및 실습만족도에 미치는 효과를 검증하고자 하였다. 이러한 연구목적을 달성하기 위하여 치의학 전공 대학생 66명을 대상으로 3D 모델링 어플리케이션을 활용한 실험집단과 텍스트와 삽화로 구성된 2차원 수업자료를 활용한 통제집단에 각각 33명씩 배정하여 실험을 하였다. 연구결과 첫째, 2차원 수업자료를 활용한 과제정보 집단(통제집단)이 3차원 멀티미디어를 활용한 모바일 과제정보 집단보다 치아형태에 대한 이해가 높은 것으로 나타났다. 둘째, 3차원 멀티미디어를 활용한 수업이 학생들의 치아카빙 수행 능력 향상에서 유의미한 효과가 나타났다. 셋째, 3차원 멀티미디어를 활용한 모바일 과제정보 제시 집단의 수업만족도가 통제집단보다 더 높은 것으로 나타났다. 따라서 치아형태학 수업에서 3D 모델링을 제공하는 것은 수업만족도를 높여주며, 치아카빙 수행 향상을 돕는 교육콘텐츠로 활용이 가능할 것으로 보인다.