• Journal of the Korea Computer Industry Society
• /
• v.2 no.12
• /
• pp.1533-1540
• /
• 2001

In this paper, we described extraction method of electrical parameters and modeling method of PCB nets on PCB design process. To analyze electrical characteristics of real PCB structure, we selected a cache memory system as an experimental board and designed 6 layer PCB substrate. For extraction of the electrical parameters, we divided circuit elements into the components of conductor types which are wires, via holes, BGA balls etc. and combined the calculated value by real net structure to modeling the PCB nets. We analyzed the electrical characteristics of the PCB nets with the simulation tools of SPICE and XNS. The simulation analysis has shown that the maximum signal delay was 2.6ns and the maximum crosstalk noise was 281 mV and we found that the designed substrate was adequate to system specification.

• The Transactions of the Korea Information Processing Society
• /
• v.7 no.7
• /
• pp.2028-2040
• /
• 2000

A study on workflow as an automated business processing system is done recently. This appear proposes a method to verify commitability and integrity of workflow specifications, which include various dependencies between parallel tasks, using petri nets. For this, firstly, e describe briefly workflow specification method using workflow graphs. Secondly, we propose a method to convert a workflow graph into a petri net to verify workflow specifications. Thirdly, we suggest the commitability verification method using petri nets to check whether workflow specifications can commit or not and the integrity verification method to check whether invalid components exist or not. Lastly, we implement the proposed verification method and propose a defect extraction method.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.47 no.4
• /
• pp.338-343
• /
• 2011

To obtain the effective sampling estuarine fauna by a passive net in the West Sea of Korea occurring strong tide, catch were collected by bag nets with various sampling trials off Ganghwa Island in November 2009. We compared the difference of community structures (on spring tide vs. neap tide, total sample vs. subsample and 4 nets vs. 1 net) with each species composition as a sampling unit by the Pearson chi-square test. Number of individual at the spring tide was more abundant than that at the neap tide (p<0.0001) although number of species at the spring tide was not significantly different with that at the neap tide (p=0.174). Both number of species (p=0.138) and number of individual (p=0.096) were not significantly different between total sample and random subsample. Number of species was not significantly different between the subsample by 1 net and the subsample by 4 nets (p=0.515), but number of individual was a little different on both samples (p=0.024). In conclusion, we suggest the subsample by 1 net at spring tide as the effective sampling estuarine fauna by a passive net in the West Sea occurring strong tide.

• The Journal of the Korea Contents Association
• /
• v.9 no.1
• /
• pp.45-52
• /
• 2009

In this paper, we develop queueing network models of communication networks with reliability model considering link failures. The reliability of a communication network with a virtual connection exposed to link failures is analyzed. Stochastic Reward Nets (SRN) is an extension of stochastic Petri nets and provides compact modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. It is shown that SRN modeling is well suited to specify, automatically generate and solve for reliability under rerouting. Markov models using SRN are developed and solved to depict various rerouting caused by link failures and reliability analysis in communication networks.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.42 no.5
• /
• pp.523-526
• /
• 2009

Biodegradable polybutylene succinate (BPS) multifilament were designed to degrade upon disposal by the action of afforestration of Ecklonia cava. Matured thalli of E. cava were collected at Jeju for zoospore collection and the substrate for zoospores were BPS multifilament (12 mm, 500 Td/96). The materials were made as nets of $1\;m^2$ with a cross stripes of 10 cm. The unit biodegradable nets bearing germlings of E. cava was moved into Wando where the place is conducting intensive seaweed cultivation in Korea for 5 months of nursery culture until they grew to 10 cm in length after which the nets were transplanted into the sea bed at Jeju at a depth of 12 m and the algal growth was monitored from May 2007 to December 2008. This is the first instance of using the BPS materials for seaweed afforestation to avoid any environmental problems.

• Journal of Korea Multimedia Society
• /
• v.5 no.6
• /
• pp.704-711
• /
• 2002

Multimedia communication systems are characterized by supporting three different typer of services such as circuit switched services, and packet switched real Lime and non real time services. The wireless channels in a cell ate allocated by calls of these different service classes and the different service requirements have to be met. SRN is an extension of stochastic Petri nets and provides compact Modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. In this paper, we present a SRN model for performance analysis of channel allocation of multimedia mobile communication systems. The key contribution of this paper constitutes the Petri nets modeling techniques instead of complicate numerical analysis of Markov chains and easy way of performance analysis for channel allocations under SRN rewards concepts.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.1
• /
• pp.101-108
• /
• 1997

The initial token value required to the optimal performance of discrete event systems can be decided by Sum of Delay Time and Synchronic Time ratio, which are new synchronic variables in Timed Place Petri Nets. For the system consisting of two Live-and-Bounded circuits(LB-circuits) fused in common Transition-Transition-Path or common Place-Place-Path, we prove that the Synchronic Time Ratio is the initial token ratio between two LB-circuits to optimally perform system functions. These results are generalized and formulated as a theorem. The initial tokens of a specific place can imply shared resources. Using the theorem, we can decide the minimum number of the shared resources to obtain the optimal performance, and minimize the idling time of resources. As an example, an automated assembly system is modeled by Timed Place Petri Net, and the initial tokens to achieve the optimal system performance are identified. All the values are verified by simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.6
• /
• pp.1979-1995
• /
• 2015

Network convergence is regarded as the development tendency of the future wireless networks, for which self-organization paradigms provide a promising solution to alleviate the upgrading capital expenditures (CAPEX) and operating expenditures (OPEX). Self-optimization, as a critical functionality of self-organization, employs a decentralized paradigm to dynamically adapt the varying environmental circumstances while without relying on centralized control or human intervention. In this paper, we present comprehensive surveys of heterogeneous networks (HetNets) and investigate the enhanced self-optimization models. Self-optimization approaches such as dynamic mobile access network selection, spectrum resource allocation and power control for HetNets, etc., are surveyed and compared, with possible methodologies to achieve self-optimization summarized. We hope this survey paper can provide the insight and the roadmap for future research efforts in the self-optimization of convergence networks.

• Journal of KIISE:Computer Systems and Theory
• /
• v.27 no.6
• /
• pp.599-607
• /
• 2000

This paper suggests an efficient reachability analysis method of bounded petri nets. Reachability analysis is a fundamental basis for studying the dynamic properties of any discrete event systems. However, it takes at least exponential execution time and memory space to verify in general petri nets. That is, state space explosion problem may occur. In this paper, we attack problems of previous approaches - state space explosion and restrictions to applicable petri net classes - by formulating the reachability problem as set operation over structural relations among places on an unfolding.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.8 no.2
• /
• pp.177-184
• /
• 1988

The method of least squares has been applied to the static data, but it was not applications for the processing of observed values accompaning real-time variation. In this paper, having been considered all observations to be the function of time, leveling nets were analized dynamically by introducing the concept of time to conventional method of least squares. As a results, the method of dynamic least squares was well applicable to the adjustment of leveling nets.