How to Compare the Scientific Contributions between Research Groups

We present a method to analyse the scientific contributions between research groups. Given multiple research groups, we construct their journal/proceeding graphs and then compute the similarity/gap between them using network analysis. This analysis can be used for measuring similarity/gap of the topics/qualities between research groups' scientific contributions. We demonstrate the practicality of our method by comparing the scientific contributions by Korean researchers with those by the global researchers for information security in 2006 - 2008. The empirical analysis shows that the current security research in South Korea has been isolated from the global research trend

Sticker land: Interactive educational game

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Hybrid Spam Filtering for Mobile Communication

Spam messages are an increasing threat to mobile communication. Several mitigation techniques have been proposed, including white and black listing, challenge-response and content-based filtering. However, none are perfect and it makes sense to use a combination rather than just one. We propose an anti-spam framework based on the hybrid of content-based filtering and challenge-response. There is the trade-offs between accuracy of anti-spam classifiers and the communication overhead. Experimental results show how, depending on the proportion of spam messages, different filtering %%@ parameters should be set.Comment: 6 pages, 5 figures, 1 tabl

An Experimental Syntactic Study of Binding: A Case Study of Korean Long-Distance Anaphor caki

PACLIC 23 / City University of Hong Kong / 3-5 December 200

Brain-like synapse thin-film transistors using oxide semiconductor channels and solid electrolytic gate insulators

Human brain has astonishing advantages such as tolerance to system faults, low power consumption, and adaptive learning ability from pre-obtained data unlike conventional computer system with Von Neumann architecture. One of the most attractive benefits of human brain is an ability of parallel processing. Considering these advantages, new types of devices featured to emulate the human brain are quite demanding. These artificially designed systems are called neuromorphic systems, in which neurons are inspired by electronic signals applied to synapses. They can be useful components in artificial perception and action systems. Recently, many types of electronic devices mimicking the functions of human brain have been energetically studied [1-2]. However, these devices have following limitations. First, it needs additional external memories for storing synapse information because CMOS devices cannot work as nonvolatile memories. Second, conventional Si-based electronic technology is not compatible with large-area electronics implemented on glass or flexible substrates. In this work, we propose new type of synapse device with thin-film transistor (TFT) configuration for realizing simple device structure and operation for synaptic learning, in which oxide semiconductor In-Ga-Zn-O (IGZO) and solid electrolytes, such as poly(4-vinylphenol) - sodium β-alumina (PVP-SBA) and polypropylene carbonate (PPC), are employed as active channel and solid-electrolytic gate insulators for TFT operations, respectively. Solid electrolytes can be promising for controlling the synaptic weights by exploiting the movements of charged ions within the electrolytes. Lithium and sodium ions are transported in PPC and PVP-SBA, respectively. Synaptic weights can be determined as the modulated channel conductance and be estimated from the gradual variations in drain currents. Figs. 1(a) and 1(b) show cross-sectional view of fabricated synapse TFT using PVP-SBA gate insulator and schematic structures of biological synapse & neuron, respectively. Figs. 2(a) and 2(b) showed the variations in output drain currents as functions of two input pulse parameters, amplitude and width. First, the voltage pulses were repeatedly applied to the gate terminal one-hundred times with a fixed pulse width of 50 ms. The output drain current gradually increased with increasing the number of pulses [Fig. 2(a)]. When the pulse amplitude was varied to 10 and 20 V at ten-time applications, the value of obtained output drain current markedly increased and the current ratio for two conditions were calculated to be approximately 2.6. These results clearly suggest that the synaptic weights could be more fortified when larger voltage signals (20 V) were employed for synaptic operations. In other words, it means that the quantity of residual memory or response significantly increased with stronger stimuli. When pulse signals with a fixed amplitude of 10 V were applied with variations in pulse widths of 10, 50, and 100 ms. The output drain currents more quickly increased for longer pulses [Fig. 2(b)]. The obtained current ratios of 100-ms conditions to 10-ms condition at ten- and one-hundred-time applications were estimated to be approximately 3.1 and 2.1, respectively. These results emulate the changes in learning time at a single event. Our proposed synapse TFTs can be a suitable candidate for the next-generation low-power large-area electronics such as neuromorphic systems and flexible bio-mimicking devices. Please click Additional Files below to see the full abstract

Modeling and Analysis of Mobility Management in Mobile Communication Networks

Many strategies have been proposed to reduce the mobility management cost in mobile communication networks. This paper studies the zone-based registration methods that have been adopted by most mobile communication networks. We focus on two special zone-based registration methods, called two-zone registration (2Z) and two-zone registration with implicit registration by outgoing calls (2Zi). We provide a new mathematical model to analyze the exact performance of 2Z and 2Zi. We also present various numerical results, to compare the performance of 2Zi with those of 2Z and one-zone registration (1Z), and show that 2Zi is superior to 2Z as well as 1Z in most cases

On the limit of the sequence {Cm(D)}m=1∞\left\{ C^m(D) \right\}_{m=1}^{\infty} for a multipartite tournament DD

For an integer $k \ge 2$, let $A$ be a Boolean block matrix with blocks $A_{ij}$ for $1 \le i,j \le k$ such that $A_{ii}$ is a zero matrix and $A_{ij}+A_{ji}^T$ is a matrix with all elements $1$ but not both corresponding elements of $A_{ij}$ and $A_{ji}^T$ equal to $1$ for $i \neq j$. Jung~{\em et al.} [Competition periods of multipartite tournaments. {\it Linear and Multilinear Algebra}, https://doi.org/10.1080/03081087.2022.2038057] studied the matrix sequence $\{A^m(A^T)^m\}_{m=1}^{\infty}$. This paper, which is a natural extension of the above paper and was initiated by the observation that $\{A^m(A^T)^m\}_{m=1}^{\infty}$ converges if $A$ has no zero rows, computes the limit of the matrix sequence $\{A^m(A^T)^m\}_{m=1}^{\infty}$ if $A$ has no zero rows. To this end, we take a graph theoretical approach: noting that $A$ is the adjacency matrix of a multipartite tournament $D$, we compute the limit of the graph sequence $\left\{ C^m(D) \right\}_{m=1}^{\infty}$ when $D$ has no sinks