• 한국컴퓨터그래픽스학회논문지
• /
• 제13권2호
• /
• pp.1-15
• /
• 2007

본 논문에서는 혼합현실 기술과 관련된 국내 외의 최근 연구개발 동향과 사례들을 살펴보고, 사용된 기술내용과 기술적 한계 극복을 위한 발전 방향을 논한다. 혼합현실 기술은 실 세계와 가상 세계를 실시간으로 혼합하여 사용자에게 제공함으로써 정보 사용의 효율성과 효과성을 극대화하는 기술이며, 이는 향후 IT 기술 전분야의 발전과 변화에 많은 영향을 줄 '주목해야 할 기술'이다. 혼합현실 기술이 사용자들에게 쉽게 받아들여지고, 보다 적극적으로 널리 활용되기 위해서는 HMD(Head Mount Display), 트래킹 시스템, 실시간 랜더링 및 정합 등 기술적 한계의 극복과 혼합현실에 특화된 사용자 상호작용 기술 개발 및 응용 서비스 창출 그리고 사회적인 용인 한계의 극복 등이 요구된다.

• 인지과학
• /
• 제26권4호
• /
• pp.435-452
• /
• 2015

최근 개체 링킹에 대한 연구들은 지식 베이스를 외부 자원으로 사용하여 실세계의 지식과 의미적인 관련도를 통해 중의성을 해소하는데 중점을 두고 있다. 지식 베이스를 사용한 개체 링킹은 신문기사나 블로그 포스트 등에서는 좋은 성능을 보이지만, 마이크로블로그에서는 짧은 텍스트 길이와 지식 베이스에 존재하지 않는 주제를 다루는 특성 때문에 비교적 낮은 성능을 보인다. 본 논문에서는 140자가 되지 않는 짧은 텍스트 내에서 실시간으로 빠르게 정보를 공유하는 특성을 가지는 마이크로블로그에서 나타나는 개체명의 중의성을 해소하는 방법을 제안한다. 제안하는 방법은 지식 베이스만 사용하는 개체 링킹의 한계를 극복하기 위해 마이크로블로그 사용자 기록과 뉴스 기사를 이용하고, 지식 베이스에 존재하는 특정 엔트리로 개체 링킹을 수행한다. 본 논문에서는 개체명을 포함하는 한국어 트윗을 추출하여 데이터를 구축하였다. 성능 평가는 정확도 지표(시스템이 정답으로 판정한 데이터 개수/전체 데이터 개수)를 사용하였으며, 제안하는 시스템은 구축한 데이터에서 기존 지식 베이스만 사용한 개체 링킹 시스템보다 높은 67.7%의 정확도를 나타내었다.

• International journal of advanced smart convergence
• /
• 제5권1호
• /
• pp.34-46
• /
• 2016

Networked Control System (NCS) has evolved in the past decade through the advances in communication technology. The problems involved in NCS are broadly classified into two categories namely network issues due to network and control performance due to system network. The network problems are related to bandwidth allocation, scheduling and network security, and the control problems deal with stability analysis and delay compensation. Various delays with variable length occur due to sharing a common network medium. Though most delays are very less and mostly neglected, the network induced delay is significant. It occurs when sensors, actuators, and controllers exchange data packet across the communication network. Networked induced delay arises from sensor to controller and controller to actuator. This paper presents an adaptive delay compensation process for efficient control. Though Smith predictor has been commonly used as dead time compensators, it is not adaptive to match with the stochastic behavior of network characteristics. Time delay adaptive compensation gives an effective control to solve dead time, and creates a virtual environment using the plant model and computed delay which is used to compensate the effect of delay. This approach is simulated using TrueTime simulator that is a Matlab Simulink based simulator facilitates co-simulation of controller task execution in real-time kernels, network transmissions and continuous plant dynamics for NCS. The simulation result is analyzed, and it is confirmed that this control provides good performance.

• International Journal of Control, Automation, and Systems
• /
• 제4권6호
• /
• pp.782-787
• /
• 2006

The role of Unmanned Aircraft Vehicles(UAVs) has been increasing significantly in both military and civilian operations. Many complex systems, such as UAVs, are difficult to model accurately because they exhibit nonlinearity and show variations with time. Therefore, the control system must address the issues of uncertainty, nonlinearity, and complexity. Hence, identification of the mathematical model is an important process in controller design. In this paper, attitude dynamics identification of UAV is investigated. Using the flight data, nonlinear state space model for attitude dynamics of UAV is derived and verified. Real time simulation results show that the model dynamics match experimental data.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
• /
• pp.37-40
• /
• 2001

The most important issues in gesture recognition are the simplification of algorithm and the reduction of processing time. The mathematical morphology based on geometrical set theory is best used to perform the real-time processing. A key idea of the algorithm proposed in this paper is to apply morphological shape decomposition. The primitive elements extracted from a hand gesture have very important information including the directivity of the hand gestures. Based on this algorithm, we proposed the morphological hand-gesture recognition algorithm using feature vectors extracted from lines connecting the center points of a main-primitive element and sub-primitive elements. Through the experiments, we applied to the video contents browsing system with natural interactions and demonstrated the efficiency of this algorithm.

• 한국CDE학회논문집
• /
• 제16권1호
• /
• pp.21-30
• /
• 2011

Similarity assessment of a CAD model is one of important issues from the aspect of model re-using. In real practice, many new mechanical parts are designed by modifying existing ones. The reuse of part enables to save design time and efforts for the designers. Design time would be further reduced if there were an efficient way to search for existing similar designs. This paper proposes an efficient algorithm of similarity assessment for mechanical part model with design history embedded within the CAD model. Since it is possible to retrieve the design history and detailed-feature information using CAD API, we can obtain an accurate and reliable assessment result. For our purpose, our assessment algorithm can be divided by two: (1) we select suitable parts by comparing MSG (Model Signature Graph) extracted from a base feature of the required model; (2) detailed-features' similarities are assessed with their own attributes and reference structures. In addition, we also propose a indexing method for managing a model database in the last part of this article.

• 한국환경보건학회지
• /
• 제37권1호
• /
• pp.73-79
• /
• 2011

The growing interest in nanotechnology has resulted in increasing concern and a number of published environmental and workplace measurements for assessing occupational exposure to engineered nanomaterials. However, the amount of previous exposure data remains limited. Furthermore the data available was collected with extensive variation in terms of exposure measurement strategy, which limits the ability to pool the data in the future. In response, this paper reviewed several pertinent issues related to exposure measurement strategy to suggest a harmonized measurement strategy which would make exposure data more useful in the future, e.g. correlation between exposure metrics, relationship between activity and exposure, task-based or shift-based assessment, background concentration, limitation of personal exposure monitoring and other determinants of exposure/modeling. An improved sampling strategy for nanomaterial exposure assessment should be considered in order to maximize the use of the data from various real time monitoring instruments.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제8권11호
• /
• pp.4016-4027
• /
• 2014

Understanding network latency is important for providing consistent and acceptable levels of services in network-based applications. However, due to the difficulty of estimating applications' network demands and the difficulty of network latency modeling the management of network resources has often been ignored. We expect that, since network latency repeats cycles of congested states, a systematic classification method for network status would be helpful to simplify issues in network resource managements. This paper presents a simple empirical method to classify network status with a real operational network. By observing oscillating behavior of end-to-end latency we determine networks' status in run time. Five typical network statuses are defined based on a long-term stability and a short-term burstiness. By investigating prediction accuracies of several simple numerical models we show the effectiveness of the network status classification. Experimental results show that around 80% reduction in prediction errors depending on network status.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
• /
• pp.781-784
• /
• 1993

Most linguistic models of processes or plants known are essentially static, that is, time is not a parameter in describing the behavior of the object's model. In this paper we show two models for synchronous finite state machines (FSM) based on fuzzy logic, namely the Crisp-State-Fuzzy-Output (CSFO FSM) and Fuzzy-State-Fuzzy Output (FSFO FSM). As a result of the introduction of the FSM models, the improved architectures for fuzzy logic controller have been defined. These architectures featuring pipelined intelligent fuzzy controller are discussed in terms of dimensionality of the model. VLSI integrated circuit implementation issues of the fuzzy logic controller are also considered. The presented approach can be utilized for fuzzy controller hardware accelerators intended to work in the real-time environment.

• 한국공간정보시스템학회 논문지
• /
• 제1권1호
• /
• pp.57-67
• /
• 1999

지능형 교통체계(Intelligent Transport System: ITS)를 구현함에 있어서 반드시 필요한 상호운영성을 보장하기 위한 GIS/OGIS 측면의 두 가지의 문제 (미국의 Oak Ridge National Lab. 에서 수행하였던), 위치참조체계 및 ITS Map Datum에 대한 개괄적인 검토가 이루어졌다. 위치참조는 통신을 통한 교통정보전달 및 데이터호환을 위한 필요도구이며, ITS Map Datum은 전체 서비스 지역, 주로 지역과 지역간의, ITS서비스를 구현하기 위한 핵심으로서 도로망의 기본노드 및 관련속성의 집합이다. 이 두 요소는 ITS서비스 구현에서의 기본표준으로 요망되었고 이제 그 표준안이 제시되고 있다. 특히 실시간의 교통정보가 수집, 가공, 제공되어지는 시점에서 반드시 필요한 ITS Map Datum은 국가적인 정보인프라로의 성격을 지닌 요소로서, 위치참조를 구현함에 있어서도 필수 불가결하다. 위치참조의 프로파일이 외국으로부터 빌려서 쓸 수는 있어도, ITS Map Datum은 우리가 반드시 해결하여야 하는 부분이다. 미국 사례의 전체적 개요와 이런 과정에서 우리가 본받아야 하는 기본적, 제도적인 이슈 부분에 대한 언급이 장차 해결해야 하는 연구항목과 함께 제시되었다.