• Journal of the Korean Data and Information Science Society
• /
• v.25 no.5
• /
• pp.1039-1055
• /
• 2014

The distribution of a test statistic under a null hypothesis depends on the unknown distribution of the data and thus is unknown as well. Conditional tests replace the unknown null distribution by the conditional null distribution, that is, the distribution of the test statistic given the observed data. This approach is known as permutation tests and was developed by Fisher (Fisher, 1935). Theoretical framework for permutation tests was given by Strasser and Weber(1999). The coin package developed by Hothon et al. (2006, 2008) implements a unified approach for conditional inference via the generic independence test. Because convenient functions for the most prominent problems are available, users will not have to use the extremely flexible procedure. In this article we briefly review the underlying theory from Strasser and Weber (1999) and explain how to transform the data to perform the generic function independence test. Finally it was illustrated with a few real data sets.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.17 no.11
• /
• pp.1228-1237
• /
• 1992

Network management represents those activities which control and moitor the use of resources. Remote delegation model supports flexible and effective distribution of management functions among managers and agents, and it may cause an reliable network management in a relatively complex and high-speed networks. in this model, managers delegate to agents execution of management programs as prescribed in a management scripting language. In addition, primitives included in the management programs enable agents to monitor and control localmanaged objects effectively. We suggest management algorithms in which management scripts are delegated from managers to agents and partiality implement OSI fault management. This mans gement algorithm can effectively support delegation and control concurrent accesses to management information. Moreover, it can be easily translated into object-based concurrent programming language: ABCL. In this paper, we will scrutinize some essential aspects of this management.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.3
• /
• pp.451-458
• /
• 2015

The deployment density of AP increases as well as the density WLAN stations due to increase of WLAN use and the real performance of WLAN is degraded. To improve the performance, there are many PHY/MAC technologies and OFDMA and full duplex are promising technologies among them. In conventional OFDMA WLAN MAC relate works, there are some limitations in terms of channel utilization and collision probability. Thus, it need to research for effective channel allocation protocol. Full duplex can transmit data on the same time and same frequency resource so it can allocate channel more flexible than half duplex. In this paper, we prose the OFDMA FD-MAC(Full Duplex MAC) protocol that it allocates the sub-channels based on the idle channel information for full duplex pair. In addition, it shows the throughput improvement by performance analysis.

• Journal of Communications and Networks
• /
• v.9 no.3
• /
• pp.296-311
• /
• 2007

Mobile multi-robot teams are useful in many critical applications such as search and rescue. Explicit communication among robots in such mobile multi-robot teams is useful for the coordination of such teams as well as exchanging data. Since many applications for mobile robots involve scenarios in which communication infrastructure may be damaged or unavailable, mobile robot teams frequently need to communicate with each other via ad hoc networking. In such scenarios, low-overhead and energy-efficient routing protocols for delivering messages among robots are a key requirement. Two important primitives for communication are essential for enabling a wide variety of mobile robot applications. First, unicast communication (between two robots) needs to be provided to enable coordination and data exchange. Second, in many applications, group communication is required for flexible control, organization, and management of the mobile robots. Multicast provides a bandwidth-efficient communication method between a source and a group of robots. In this paper, we first propose and evaluate two unicast routing protocols tailored for use in ad hoc networks formed by mobile multi-robot teams: Mobile robot distance vector (MRDV) and mobile robot source routing (MRSR). Both protocols exploit the unique mobility characteristics of mobile robot networks to perform efficient routing. Our simulation study show that both MRDV and MRSR incur lower overhead while operating in mobile robot networks when compared to traditional mobile ad hoc network routing protocols such as DSR and AODV. We then propose and evaluate an efficient multicast protocol mobile robot mesh multicast (MRMM) for deployment in mobile robot networks. MRMM exploits the fact that mobile robots know what velocity they are instructed to move at and for what distance in building a long lifetime sparse mesh for group communication that is more efficient. Our results show that MRMM provides an efficient group communication mechanism that can potentially be used in many mobile robot application scenarios.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.53 no.5
• /
• pp.237-241
• /
• 2004

Amorphous silicon (a-Si) films are used in a broad range of solar cell, flat panel display, and sensor. Because of the greater ease of deposition and lower processing temperature, thin films are widely used for thin film transistors (TFTs). However, they have lower stability under the exposure of visible light and because of their low field effect mobility ($\mu$$_{FE}$ ) , less than 1 c $m^2$/Vs, they require a driving IC in the external circuits. On the other hand, polycrystalline silicon (poly-Si) thin films have superiority in $\mu$$_{FE}$ and optical stability in comparison to a-Si film. Many researches have been done to obtain high performance poly-Si because conventional methods such as excimer laser annealing, solid phase crystallization and metal induced crystallization have several difficulties to crystallize. In this paper, a new crystallization process using a molybdenum substrate has been proposed. As we use a flexible substrate, high temperature treatment and roll-to-roll process are possible. We have used a high temperature process above 75$0^{\circ}C$ to obtain poly-Si films on molybdenum substrates by a rapid thermal annealing (RTA) of the amorphous silicon (a-Si) layers. The properties of high temperature crystallized poly-Si studied, and poly-Si has been used for the fabrication of TFT. By this method, we are able to achieve high crystal volume fraction as well as high field effect mobility.

• Journal of KIISE:Databases
• /
• v.31 no.6
• /
• pp.699-709
• /
• 2004

XML is increasingly important in data exchange and information management. Starting point for retrieving the structure and integrating the documents efficiently is clustering the documents that have similar structure. The reason is that we can retrieve the documents more flexible and faster than the method treating the whole documents that have different structure. Therefore, in this paper, we propose the similar structure-based incremental clustering method useful for retrieving the structure of XML documents and integrating them. As a novel method, we use a clustering algorithm for transactional data that facilitates the large number of data, which is quite different from the existing methods that measure the similarity between documents, using vector. We first extract the representative structures of XML documents using sequential pattern algorithm, and then we perform the similar structure based document clustering, assuming that the document as a transaction, the representative structure of the document as the items of the transaction. In addition, we define the cluster cohesion and inter-cluster similarity, and analyze the efficiency of the Proposed method through comparing with the existing method by experiments.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.66 no.12
• /
• pp.1772-1781
• /
• 2017

In this study, the design methodology for alleviating the overfitting problem of Polynomial Neural Networks(PNN) is realized with the aid of two kinds techniques such as L2 regularization and Sum of Squared Coefficients (SSC). The PNN is widely used as a kind of mathematical modeling methods such as the identification of linear system by input/output data and the regression analysis modeling method for prediction problem. PNN is an algorithm that obtains preferred network structure by generating consecutive layers as well as nodes by using a multivariate polynomial subexpression. It has much fewer nodes and more flexible adaptability than existing neural network algorithms. However, such algorithms lead to overfitting problems due to noise sensitivity as well as excessive trainning while generation of successive network layers. To alleviate such overfitting problem and also effectively design its ensuing deep network structure, two techniques are introduced. That is we use the two techniques of both SSC(Sum of Squared Coefficients) and $L_2$ regularization for consecutive generation of each layer's nodes as well as each layer in order to construct the deep PNN structure. The technique of $L_2$ regularization is used for the minimum coefficient estimation by adding penalty term to cost function. $L_2$ regularization is a kind of representative methods of reducing the influence of noise by flattening the solution space and also lessening coefficient size. The technique for the SSC is implemented for the minimization of Sum of Squared Coefficients of polynomial instead of using the square of errors. In the sequel, the overfitting problem of the deep PNN structure is stabilized by the proposed method. This study leads to the possibility of deep network structure design as well as big data processing and also the superiority of the network performance through experiments is shown.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.2
• /
• pp.439-446
• /
• 2011

In this paper, we proposed and implemented a dedicated hardware for Huffman coding which is a method of entropy coding to use compressing multimedia data with video coding. The proposed Huffman codec consists Huffman encoder and decoder. The Huffman encoder converts symbols to Huffman codes using look-up table. The Huffman code which has a variable length is packetized to a data format with 32 bits in data packeting block and then sequentially output in unit of a frame. The Huffman decoder converts serial bitstream to original symbols without buffering using FSM(finite state machine) which has a tree structure. The proposed hardware has a flexible operational property to program encoding and decoding hardware, so it can operate various Huffman coding. The implemented hardware was implemented in Cyclone III FPGA of Altera Inc., and it uses 3725 LUTs in the operational frequency of 365MHz

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.10a
• /
• pp.194-196
• /
• 2017

is a MOBA game developed by 2015 at the Tentent's Tianmei Studios. The operation of the game was very successful, ranking first in the global mobile gaming revenue list in May 2017. However, most of the discussion about this game are the moral critique of game addiction. In fact, a game's success is closely related to the Marketing strategy beyond the contents of the game. This research using a neutral point of view to see the communication modes of during the early, development and outbreak period, analyze the integrated marketing communication strategy (IMC) through the method of case study, and concluded that the key to the success of IMC is the flexible use of various communication methods to achieve a three-dimensional offensive according to the famous Synergy Theory. It is also hoped that this article will be helpful for practitioners to realize the importance of Publicity and promotion of other game products.

• Journal of KIISE:Computing Practices and Letters
• /
• v.5 no.5
• /
• pp.564-573
• /
• 1999

Recently, as the development and use of distributed multimedia services are growing explosively in every aspects of our lives, administrators of multimedia services are very concerned with providing users with reliable and efficient services. However, the management of distributed multimedia services is a very complex and troublesome work such that a flexible but powerful management system is necessary. This paper proposes a management system for managing CORBA-based distributed multimedia services. We have developed an architecture for the management system and defined a set of management services needed to monitor and control distributed multimedia services. The architecture consists of several objects, which perform configuration management, fault management, security management and event management. A generic distributed multimedia service (DMS) MIB has been defined for the management of various multimedia services and applications. In addition, as a proof of concept, we have developed a Web-based management system for a CORBA-based distributed multimedia system called MAESTRO. The prototype management system uses OrbixWeb to interface with the management server which is implemented as a set of CORBA objects. Though our management system has been developed for distributed multimedia services, it can easily manage other CORBA-based services and applications.