• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.6
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• pp.1037-1044
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• 2014

A (t,n) threshold secret sharing scheme is the scheme which allows a trusted party to distribute the shares among n participants in such a way that any t of them can recover the original secret, but any group knowing only t-1 or fewer shares can not. Recently, Eslami et al. and Tadayon et al. proposed threshold multi-secret sharing schemes, respectively. They proposed that their schemes don't require secure channels. But, without secure channels in their schemes, everyone can get the shares and find the secrets. The proposed scheme does not use secure channels and only t participants can solve the equations of the system from the delivered share shadows and find the secrets.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.291-296
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• 2012

In this Paper, we propose a multi-hop transmission in cognitive underlay network. In Secondary network, We assume that a secondary source S attempts to transmit D its signal to a secondary destination via N+1 hops with help of N relays $R_1$, $R_2$, ${\ldots}$, $R_N$. At hop k between relay $R_k$ and relay $R_{k+1}$. we assume that there is a primary user $PU_k$. In this paper, we assume that these channels are Rayleigh fading channels. In underlay network, the secondary transmitter has to adapt its power so that the interference caused at the primary user is less than a maximum interference threshold. considering the hop transmission between the transmitter and the repeater, we find transmit power and signal-to-noise ratio(SNR). Between the transmitter from the receiver depending on the number of relay in the underlay network, we compared to find the transmit power and signal-to-noise ratio(SNR). Finally we find optimal number of relay and optimal threshold value.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.11
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• pp.2607-2612
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• 2014

In this paper, we propose a distributed user scheduling with transmit power control based on the amount of interference inflicted to other BSs in multi-cell uplink networks. Assuming that the channel reciprocity time-division duplexing(TDD) system is used, the channel state information (CSI) can be obtained at each user from pilot signals from other BSs. The amount of generating interference to other BSs will be calculated at each user. Especially, in this paper, we propose the threshold-based transmit power control, in which a user decrease its transmit power if its generating interference to other BSs is larger than a predetermined threshold. Simulation results show that the proposed technique significantly outperforms the existing user scheduling algorithms.

• Journal of KIISE:Computer Systems and Theory
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• v.37 no.6
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• pp.348-353
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• 2010

A threshold decryption scheme is a multi-party public key cryptosystem that allows any sufficiently large subset of participants to decrypt a ciphertext, but disallows the decryption otherwise. When performing a threshold decryption, a third party is often involved to guarantee fairness among the participants. To maintain the security of the protocol as high as possible, it is desirable to lower the level of trust and the amount of information given to the third party. In this paper, we present a threshold decryption scheme which allows the anonymity of the participants as well as the fairness by employing a semi-trusted third party (STTP) which follows the protocol properly with the exception that it keeps a record of all its intermediate computations. Our solution preserves the security and fairness of the previous scheme and reveals no information about the identities of the participants and the plaintext even though an attacker is allowed to access the storage of the STTP.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1083-1096
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• 2008

This paper proposes an energy-aware path management scheme, so-called the TBP(Threshold based Back-Pressure) algorithm, which is designed for lifetime extension of the energy-constrained wireless sensor networks. With the goal of fair energy consumptions, we extensively utilize the available paths between the source and the sink nodes. The traffic distribution feature of the TBP algorithm operates in two scales; the local and the whole routing area. The threshold and the back-pressure signal are introduced for implementing those operations. It is noticeable that the TBP algorithm maintains the scalability by defining both the threshold and the back-pressure signal to have their meanings locally confined to one hop only. Throughout several experiments, we observe that the TBP algorithm enhances the network-wide energy distribution. which implies the extension of the network lifetime. Additionally, both the delay and the throughput outcomes show remarkable improvements. This shows that the energy-aware path control scheme holds the effects of the congestion control.

• Journal of the Korea Society of Computer and Information
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• v.17 no.6
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• pp.1-11
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• 2012

As the process technology scales down, multi-core processors cause serious problems such as increased interconnection delay, high power consumption and thermal problems. To solve the problems in 2D multi-core processors, researchers have focused on the 3D multi-core processor architecture. Compared to the 2D multi-core processor, the 3D multi-core processor decreases interconnection delay by reducing wire length significantly, since each core on different layers is connected using vertical through-silicon via(TSV). However, the power density in the 3D multi-core processor is increased dramatically compared to that in the 2D multi-core processor, because multiple cores are stacked vertically. Unfortunately, increased power density causes thermal problems, resulting in high cooling cost, negative impact on the reliability. Therefore, temperature should be considered together with performance in designing 3D multi-core processors. In this work, we analyze the temperature of the cache in quad-core processors varying cache organization. Then, we propose the low-temperature cache organization to overcome the thermal problems. Our evaluation shows that peak temperature of the instruction cache is lower than threshold. The peak temperature of the data cache is higher than threshold when the cache is composed of many ways. According to the results, our proposed cache organization not only efficiently reduces the peak temperature but also reduces the performance degradation for 3D quad-core processors.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.1
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• pp.5-24
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• 2010

Data fusion is an attractive technology because it allows various trade-offs related to performance metrics, e.g., energy, latency, accuracy, fault-tolerance and security in wireless sensor networks (WSNs). Under a complicated environment, each sensor node must be equipped with more than one type of sensor module to monitor multi-targets, so that the complexity for the fusion process is increased due to the existence of various physical attributes. In this paper, we first investigate the process and performance of multi-attribute fusion in data gathering of WSNs, and then propose a self-adaptive threshold method to balance the different change rates of each attributive data. Furthermore, we present a method to measure the energy-conservation efficiency of multi-attribute fusion. Based on our proposed methods, we design a novel energy equilibrium routing method for WSNs, viz., multi-attribute fusion tree (MAFT). Simulation results demonstrate that MAFT achieves very good performance in terms of the network lifetime.

• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.159-167
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• 2023

Objective: • To detect black hole and warm hole attacks in wireless sensor networks. • To give a solution for energy depletion and security breach in wireless sensor networks. • To address the security problem using strategic decision support system. Methods: The proposed stackelberg game is used to make the spirited relations between multi leaders and multi followers. In this game, all cluster heads are acts as leaders, whereas agent nodes are acts as followers. The game is initially modeled as Quadratic Programming and also use backtracking search optimization algorithm for getting threshold value to determine the optimal strategies of both defender and attacker. Findings: To find optimal payoffs of multi leaders and multi followers are based on their utility functions. The attacks are easily detected based on some defined rules and optimum results of the game. Finally, the simulations are executed in matlab and the impacts of detection of black hole and warm hole attacks are also presented in this paper. Novelty: The novelty of this study is to considering the stackelberg game with backtracking search optimization algorithm (BSOA). BSOA is based on iterative process which tries to minimize the objective function. Thus we obtain the better optimization results than the earlier approaches.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.1
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• pp.35-46
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• 2004

In comparison with edge-emitting lasers(EELs), predicting the output power and slope efficiency of Vertical-Cavity Surface-Emitting Lasers(VCSELs) is very difficult due to the absorption loss in DBR layers. However, by using transfer matrix method(TMM), we've made possible to calculate such parameters of multi-layer structures like VCSELs. In this paper, we've calculated the threshold gain, threshold current and slope efficiency through the methodology based on TMM. Also TMM is the way of customizing the VCSEL structure for the desired threshold current and slope efficiency by changing the number of DBR mirror layers.

• Journal of the Korean Institute of Telematics and Electronics
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• v.5 no.2
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• pp.8-14
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• 1968

A linear current-pulse discriminator consisting: of a transistor monostable multivibrator and a Si tunnel diode is described. The input currant pulse range is about 50$\mu$A~5.23mA. The measured maximum linearity deviation is $\pm$0.75% in the input current pulse range mentioned above. The pulse resolving ability of the discriminator measured depends upon the bias current through the T, D. ; and, under the reverse bias current of 3mA, the resolving time is 2rs if allow the excess pulse amplitude of 5%. The threshold stability of the discriminator depends mainly upon the stability of the peak current Ip of the T. D. ; and, under the ambient temperature variation from $0^{\circ}C$ to 5$0^{\circ}C$, no bigger threshold variation than the maximum linearity deviation, i. e. $\pm$ 0.75%, was observed.