• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.195-197
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• 2006

In this paper, an interface unit is designed to efficiently monitor transmission data in Controller Area Network(CAN)-based control systems. The CAN uses a serial multi master communication protocol that efficiently supports distributed real-time control with a very high level of data integrity, and communication speeds of up to 1Mbps. The interface unit is composed of a DSP controller which collects data on the CAN bus and transfers data to a personal computer via serial communication to save and display of interesting signals. The experimental system consists of three DSP controllers which represent electronic control units of a vehicle, an interface unit for analysing the data on the bus, and a graphic monitoring program coded on the Windows platform. The validity and the effectiveness of the proposed simple type of CAN interface unit are shown through the experimental results.

• The Journal of Korean Association of Computer Education
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• v.17 no.2
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• pp.115-124
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• 2014

Hypercube and star graph are widely known as interconnection network. The embedding of an interconnection network is a mapping of a network G into other network H. The possibility of embedding interconnection network G into H with a low cost, has an advantage of efficient algorithms usage in network H, which was developed in network G. In this paper, we provide an embedding algorithm between HCN and HON. HCN(n,n) can be embedded into HON($C_{n+1},C_{n+1}$) with dilation 3 and HON($C_d,C_d$) can be embedded into HCN(2d-1,2d-1) with dilation O(d). Also, star graph can be embedded to half pancake's value of dilation 11, expansion 1, and average dilation 8. Thus, the result means that various algorithms designed for HCN and Star graph can be efficiently executed on HON and half pancake, respectively.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.8
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• pp.638-651
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• 2000

When the bandwidth resources in a packet-switched network are shared among sessions by MAX-MIN flow control each session is required to transmit its data into the network subject to the MAX-MIN fair rate which is solely determined by network loadings. This passive behavior of sessions if fact can cause seri-ous QoS(Quality of Service) degradation particularly for real-time multimedia sessions such as video since the rate allocated by the network can mismatch with what is demanded by each session for its QoS. In order to alleviate this problem we extend the concept of MAX-MIN fair bandwidth allocations as follows: Individual bandwidth demands are guaranteed if the network can accommodate them and only the residual network band-width is shared in the MAX-MIN fair sense. On the other hand if sum of the individual bandwidth demands exceeds the network capacity the shortage of the bandwidth is shared by all the sessions by reducing each bandwidth guarantee by the MAX-MIN fair division of the shortage. we present a novel flow control algorithm to achieve this extended MAX-MIN fairness and show that this algorithm can be implemented by the existing ATM ABR service protocol with minor changes. We not only analyze the steady state asymptotic stability and convergence rate of the algorithm by appealing to control theories but also verify its practical performance through simulations in a variety of network scenarios.

• Journal of the Korea Society for Simulation
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• v.27 no.4
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• pp.9-18
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• 2018

This paper proposes new algorithms of accessibility indices to analyze the connectivity of the Korean highway network. First of all, we find a transportation network that presents Korea's highway network in graphs in 2011 and 2017. And we analyze and compare the nation's highway network in 2011 and 2017 using concepts such as associated number, the relative distance, the accessibility, the degree of connectivity, the index of dispersion, the diameter of graph theory. To do this, an algorithm is presented which can easily obtain various accessibility indices from a given transportation network. Using the simulation results of this study, we can find city that is the center of traffic in the highway transportation network. In addition, cities that are included in the network but are relatively underdeveloped can be found and used as basic data for enhancing the connectivity of the nationwide traffic in the future. Moreover, the proposed algorithms of accessibility indices, which are modeled on highway transport networks, can help identify the accessibility space structure of each city and provide criteria for efficient and reasonable selection of alternatives in various regional planning processes, including transportation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.914-924
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• 2020

In this study we developed artificial network generation model, which can generate on-line social network. The suggested model can represent not only scale-free and small-world properties, but also can produce networks with various values of topological characteristics through controlling two input parameters. For this purpose, two parameter K and P are introduced, K for controlling the strength of preferential attachment and P for controlling clustering coefficient. It is found out on-line social network can be generated with the combinations of K(0~10) and P(0.3~0.5) or K=0 and P=0.9. Under these combinations of P and K small-world and scale-free properties are well represented. Node degree distribution follows power-law. Clustering coefficients are between 0.130 and 0.238, and average shortest path distance between 5.641 and 5.985. It is also found that on-line social network properties are maintained as network node size increases from 5,000 to 10,000.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 1999.12a
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• pp.21-25
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• 1999

Planning support systems(PSS) add more advanced spatial analysis functions than Geographic information systems(GIS) and intertemporal functions to the functions of spatial decision support systems(SDSS). This paper reports the continuing development of a PSS providing a framework that facilitates urban planners and civil engineers in conducting coherent deliberations about planning, design and operation & maintenance(O&M) of water-distribution networks for urban growth management. The PSS using dynamic optimization model, modeling-to-generate-alternatives, value engineering(VE) and life-cycle cost(LCC) can generate network alternatives in consideration of initial cost and O&H cost. Users can define alternatives by the direct manipulation of networks or by the manipulation of parameters in the models. The water-distribution network analysis model evaluates the performance of the user-defined alternatives. The PSS can be extended to include the functions of generating sewer network alternatives, combining water-distribution and sewer networks, eventually the function of planning, design and O&H of housing sites. Capacity expansion by the dynamic water-distribution network optimization model using MINLP includes three advantages over capacity expansion using optimal control theory(Kim and Hopkins 1996): 1) finds expansion alternatives including future capacity expansion times, sizes, locations, and pipe types of a water-distribution network provided, 2) has the capabilities to do the capacity expansion of each link spatially and intertemporally, and 3) requires less interaction between models. The modeling using MINLP is limited in addressing the relationship between cost, price, and demand, which the optimal control approach can consider. Strictly speaking, the construction and O&M costs of water-distribution networks influence the price charged for the served water, which in turn influence the. This limitation can be justified in rather small area because price per unit water in the area must be same as that of neighboring area, i.e., the price is determined administratively. Planners and engineers can put emphasis on capacity expansion without consideration of the relationship between cost, price, and demand.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1104-1113
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• 2007

As there have recently been a rapid development in a supercomputer network infrastructure and an increase in the use of wireless terminals such as a PDA and cellular phone, people realize that it is highly required that they develope a various types of application services to integrate wireless network and engage them. On top of that, because current appliances are being converted into digital domestic appliances, and network and such appliances react upon each other, domestic appliances are now evolving to Internet appliances. Thus, people eager to establish a home network, which can offer a various sorts of services to customers because such appliances can share and send the data when such appliances are connected to power lines, telephone wires, and IEEE1394. Along with this, people are also enthusiastically conducting a study on Internet Application, which monitor and control the internet appliances triggered by connecting home network and supercomputer network. This study focuses on designing and developing an integrated wireless home server by effectively integrating wire and wireless network: It can approach and control each internet appliance connected with the home network inside and outside the house. In this study we also test it with an internet appliance simulator.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.2
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• pp.1-8
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• 2019

Network externalities are essentially dynamic in that the value consumers feel about a product is affected by the size of the existing customer base that uses that product. However, existing studies on network externalities analyzed the effects of network externalities in a static way, not dynamic. In this study, unlike previous studies, the impact of network externalities on price competition in a vertically differentiated market is dynamically analyzed. To this end, a two-period duopoly game model was used to reflect the dynamic aspects of network externalities. Based on the game model, the Nash equilibria for price, sales volume, and revenue were derived and numerically analyzed. The results can be summarized as follows. First, if high-end product has strong market power, the high-end product vendor takes almost all benefits of the network externality. Second, when high-end product has strong market power, the low-end product will take over most of the initial sales volume increase. Third, when market power of high-end product is not strong, it can be seen that the effects of network externalities on the high and low-end products are generally proportional to the difference in quality. Lastly, if there exists a strong network externality, it is shown that the presence of low-end product can be more profitable for high-end product vendor. In other words, high-end product vendor has incentive to disclose some technologies for the market entrance of low-end product, even if it has exclusive rights to the technologies. In that case, however, it is shown that the difference in quality should be maintained significantly.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.9
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• pp.898-904
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• 2010

Unmanned autonomous forklifts have a great potential to enhance the productivity of material handling in various applications because these forklifts can pick up and deliver loads without an operator and any fixed guide. There are, however, many technical difficulties in developing such forklifts including localization, map building, sensor fusion, control and so on. Implementation, which is often neglected, is one of practical issues in developing such an autonomous device. This is because the system requires numerous sensors, actuators, and controllers that need to be connected with each other, and the number of connections grows very rapidly as the number of devices grows. Another requirement on the integration is that the system should allow changes in the system design so that modification and addition of system components can be accommodated without too much effort. This paper presents a network-based distributed approach where system components are connected to a shared CAN network, and control functions are divided into small tasks that are distributed over a number of microcontrollers with a limited computing capacity. This approach is successfully applied to develop an unmanned forklift.

• Korean Institute of Interior Design Journal
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• no.25
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• pp.221-228
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• 2000

These days, we face of the flood of books published, and data day by day. But there are some trouble to serve the knowlodge and date to the users efficently with a single library. Thats why we think about the way of the cooporation and the connection in modern library for the method of widening the service. As the result of the issue, the establishment for the relation of each library is needed to be done, and the composition of the public library network in same area and limit are also needed. Establishing the library network, the civil life will be much influenced by the service of a library. With the existing ways, library cant arrange data efficently by them selves, and the users are limited. But the library network collect the data with alloting the work to each portion, so it can be possible to gather the specipic data, and the cost caused by needless and overlapped data can be decreased remarkably. Furthermore, the location of the library can be closer than the existing one due to the less cost to maintain the library. As I explained, the convenience of using the library can make an effect on more people to use a library than before.