• Journal of Institute of Control, Robotics and Systems
• /
• v.10 no.10
• /
• pp.878-886
• /
• 2004

Uncertainties are inevitable in robotic assembly in unstructured environment since it is difficult to construct fixtures to guide motions of robots. This paper proposes an augmented Petri net and an algorithm to adapt the assembly model on-line during actual assembly process. The augmented Petri net identifies events using force and position information simultaneously. Unmodeled contact states are identified and incorporated into the model on-line. The proposed method increases the level of intelligence of the robot system by enhancing the autonomy. The proposed method is evaluated by simulation and experiments with L-type peg-in-hole assembly using a two-arm robot system.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.3
• /
• pp.9-17
• /
• 2007

This paper introduces a Petri Net-based multimedia programming method. For this purpose, we are proposing MPN(Multimedia Petri Net) which can be used for representing a multimedia scenario. We are also introducing methods to analyze a MPN with which we can detect some kinds of design faults in the scenario. A multimedia program replays the scenario by interpreting the MPN. A method to implement such a multimedia program is also discussed. Our multimedia program provides the manipulation functions of stop, play, fast forward. rewind, and fast rewind. There are many varieties of Petri Net. Several of them are for modeling multimedia scenarios. They all have been used for synchronization analysis. But none of them were used for replaying multimedia scenario. We have extended these nets to MPN. A MPN model contains not only the flow of a scenario but also all the information associated with the data units. Therefore, our player can play the multimedia scenario by interpreting the MPN.

• Journal of Communications and Networks
• /
• v.18 no.5
• /
• pp.784-795
• /
• 2016

In this paper, we investigate the resource allocation problem in time-varying heterogeneous wireless networks (HetNet) with multi-homing user equipments (UE). The stochastic optimization model is employed to maximize the network utility, which is defined as the difference between the HetNet's throughput and the total energy consumption cost. In harmony with the hierarchical architecture of HetNet, the problem of stochastic optimization of resource allocation is decomposed into two subproblems by the Lyapunov optimization theory, associated with the flow control in transport layer and the power allocation in physical (PHY) layer, respectively. For avoiding the signaling overhead, outdated dynamic information, and scalability issues, the distributed resource allocation method is developed for solving the two subproblems based on the primal-dual decomposition theory. After that, the adaptive resource allocation algorithm is developed to accommodate the timevarying wireless network only according to the current network state information, i.e. the queue state information (QSI) at radio access networks (RAN) and the channel state information (CSI) of RANs-UE links. The tradeoff between network utility and delay is derived, where the increase of delay is approximately linear in V and the increase of network utility is at the speed of 1/V with a control parameter V. Extensive simulations are presented to show the effectiveness of our proposed scheme.

• Proceedings of the IEEK Conference
• /
• 2003.07c
• /
• pp.2795-2798
• /
• 2003

본 논문에서는 국내에서 개발하고 있는 과학로켓용 발사통제시스템(FCS, Fire Control System)의 시퀀스제어의 처리 영역을 PLC 시스템을 사용하여 구현하였다. 프로세서의 이중화를 통하여 Hot Backup 시스템을 구축하고 ControlNet 네트워크［l］［2］를 기반으로 하는 프로세서와 I/O 간의 통신을 이용하였다. 먼저 로켓 발사통제시스템의 개요 및 주요 임무에 대하여 설명하고 기존에 사용된 발사통제시스템 구성을 분석하였다. PLC 시스템의 개요와 CPU 동작 내용 그리고 ControlNet 통신방식에 대하여 설명하고 프로세서를 이중화한 시스템을 제안하였다. 또한 이중화된 프로세서의 Switchover［2］방법을 알아보고 이러한 조건에 따른 PLC 시스템을 응용한 발사 통제시스템을 구성하여 이를 위해 작성된 시스템 운용 Ladder Diagram 프로그램에 대한 기술을 논하였다. 개발된 PLC 시스템의 구성을 제시하고 발사체 및 각종 지원시설과 연계한 시험을 통하여 성능을 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2006.05a
• /
• pp.967-970
• /
• 2006

정보 보호의 목표는 정보자산의 기밀성, 무결성, 가용성을 보장함으로써 정보시스템의 신뢰성과 안전성을 확보하고 이를 통하여 기관이나 조직에서 추구하는 사업에 대한 영속성 보장의 기반을 제공하는 것이다. 접근 제어는 정보 보호의 목표인 기밀성, 무결성을 하기 위한 수단으로 많이 사용된다. 즉, 인가받지 않은 주체에게는 접근을 허용하지 않고, 인가된 주체에 대해서는 신뢰성 있는 정보를 제공하기 위해 정보에 대한 접근 제어를 한다. 그러나 가용성 측면을 무시하고 기밀성과 무결성만을 지나치게 강조할 경우 사용자에게 제공되는 정보는 이미 과거의 정보가 되어 아무런 가치가 없을 수도 있다. 이에 본 논문에서는 정보 보호의 3대 목표를 모두 만족하는 접근제어 시스템을 구축하는데 있어서 바람직한 방향을 제시하고자 한다.

• Journal of Pharmaceutical Investigation
• /
• v.23 no.2
• /
• pp.97-102
• /
• 1993

Hospital pharmacy services are divided into dispensing affairs for inpatients and outpatients, pharmaceutical service, stock control, intravenous admixture service, drug information service, pharmacokinetic consultation service, education and research work, etc. But among those affairs, dispensing affair for outpatient is perceived as the most important work in Korea, because it is linked directly with hospital service for patients. Therefore, total computer system for dispensing area was adopted from opening point of hospital in 1989 in Asan Medical Center. Utilization of computer system for outpatient dispensing area is as follows; 1) Order communication system of prescription by Total Hospital Information System, 2) Automatic print-out system of direction for use by sticker connected with on-line net work, 3) Use of automatic tablet counting and packaging machines connected with on-line net work. Those computer system resulted in curtailment of pharmacy manpower and shortening of waiting-time for outpatient.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2018.05a
• /
• pp.633-635
• /
• 2018

The compensation characteristics of the distorted WDM channels compensated for by dispersion management (DM) and optical phase conjugation in the long-haul (50 fiber spans ${\times}$ 80 km) transmission link with the randomly distributed single mode fiber (SMF) length and residual dispersion per spans (RDPS) are investigated as a function of the arrangement of SMF and dispersion compensating fiber (DCF) and the control position of net residual dispersion (NRD).

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.2
• /
• pp.322-330
• /
• 1994

SIBs(Service Independent Building block) are defined in CCITT advanced intelligent network concept model for supporting various services in the future. This paper describes the protocol modeling and verification for basic call process SIB. For modeling, we use Petri Net and verify this modeling by analyzing reachability tree of Petri Net. Results of this paper should be used for design and implementation of basic call process SIB.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.12
• /
• pp.1009-1014
• /
• 2001

The ladder diagram (LD) for programmable logic controllers (PLCs) ar responsible for much important roles in advance industrial automation. As automated systems become more complex the design procedures of the system become more difficult as well. Hence. the design automation issues based on discrete event models(DEMs) are receiving more attention. One of the popular ways of tackling these problems is employing Petri nets. In this paper, we use the modified automation Petri net(MAPN) to model the manufacturing system and the modified token passing logic (MTPL) method conversion (ECC) algorithm based on the MAPN and the MTPL Finally, an example of the manufacturing system is provided to illustrate the proposed ECC algorithm.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.15 no.5
• /
• pp.145-153
• /
• 2012

To obtain basic information for evaluating resistance of soil acidification for growth, net photosynthesis, $N_2$ fixation rate and nutrient status of Alnus firma and Alnus hirsuta seedlings grown in brown forest soil acidified with $H_2SO_4$ or $HNO_3$ solution were investigated (control (pH=5.9), LN (pH=5.0; Low levels of Nitric acid), HN (pH=4.0; High levels of Nitric acid), LS (pH=5.0; Low levels of Sulfuric acid), and HS (pH=4.0; High levels of Sulfuric acid)). The shoot dry weight of Alnus firma and Alnus hirsuta and the root dry weight of Alnus hirsuta seedlings grown in the HN, LS and HS were significantly less than that of the seedlings grown in the control. The Chlorophyll a/b ratio in leaves of Alnus firma at LN, LS and HS was significantly lower than that of control. The concentration of N in leaves of Alnus hirsuta at HS was significantly higher than that of control. The net photosynthetic rate of Alnus firma and Alnus hirsuta seedlings at LN and HN was higher than that of control. Based on the results, we concluded that the negative effects of soil acidification due to sulfate deposition are greater than those of soil acidification due to nitrate deposition on growth, net photosynthesis and $N_2$ fixation rate of Alnus firma more than Alnus hirsuta.