• International Journal of Contents
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• 제8권2호
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• pp.7-12
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• 2012

Imbalanced data sets are difficult to be classified since most classifiers are developed based on the assumption that class distributions are well-balanced. In order to improve the error back-propagation algorithm for the classification of imbalanced data sets, a new error function is proposed. The error function controls weight-updating with regards to the classes in which the training samples are. This has the effect that samples in the minority class have a greater chance to be classified but samples in the majority class have a less chance to be classified. The proposed method is compared with the two-phase, threshold-moving, and target node methods through simulations in a mammography data set and the proposed method attains the best results.

• 한국멀티미디어학회논문지
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• 제18권4호
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• pp.499-505
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• 2015

Security supports are a significant factor in the design of mobile ad hoc networks. In the dynamic topology where the node changes frequently, private key generation and revocation for newly joining and leaving nodes must be considered. In addition, the identities of individual nodes must be protected as well in mobile networks to avoid personal privacy concerns. This paper proposes ID-based private key revocation scheme and non-interactive key agreement scheme in anonymous MANETs. The proposed scheme provides the user privacy using pseudonyms and private key generation and revocation schemes with consideration of dynamic user changes. Therefore, our schemes can be applied in dynamic and privacy-preserving MANETs which are helpful to share multimedia data.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.460-462
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• 2004

The control of the data retention time is a main issue for realizing future high density dynamic random access memory. There are several leakage current mechanisms in which the stored data disappears. The mechanisms of data disappear is as follow, 1 )Junction leakage current between the junction, 2) Junction leakage current from the capacitor node contact, 3)Sub-threshold leakage current if the transfer transistor is affected by gate etch damage etc. In this paper we showed the plasma edge damage effect to find out data retention time effectiveness. First we measured the transistor characteristics of forward and reverse bias. And junction leakage characteristics are measured with/without plasma damage by HP4145. Finally, we showed the comparison TRET with etch damage, damage_cure_RTP and hydrogen_treatment. As a result, hydrogen_treatment is superior than any other method in a curing plasma etch damage side.

• Journal of the Korean Data and Information Science Society
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• 제13권1호
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• pp.97-104
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• 2002

Regression trees, a technique in data mining, are constructed by splitting function-a independent variable and its threshold. Lee (2002) considered one-sided purity (OSP) and one-sided extreme (OSE) splitting criteria for finding a interesting node as early as possible. But these methods cannot be crossed each other in the same tree. They are just concentrated on OSP or OSE separately in advance. In this paper, a new splitting method, which is the combination and extension of OSP and OSE, is proposed. By these combined criteria, we can select the nodes by considering both pure and extreme in the same tree. These criteria are not the generalized one of the previous criteria but another option depending on the circumstance.

• 한국소음진동공학회논문집
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• 제16권11호
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• pp.1149-1157
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• 2006

Donoho et al. suggested a wavelet thresholding denoising method based on discrete wavelet transform. This paper proposes an improved denoising method using a new thresholding function based on translation-invariant wavelet for underwater acoustic measurement. The conventional wavelet thresholding denoising method causes Pseudo-Gibbs phenomena near singularities due to the lack of translation-invariant of the wavelet basis. To suppress Pseudo-Gibbs phenomena, a denoising method combining a new thresholding function based on the translation-invariant wavelet transform is proposed in this paper. The new thresholding function is a modified hard-thresholding to each node according to the discriminated threshold so as to reject unknown external noise and white gaussian noise. The experimental results show that the proposed method can effectively eliminate noise, extract characteristic information of radiated noise signals.

• 진공이야기
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• 제3권1호
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• pp.16-21
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• 2016

FinFETs are able to be scaled down to 22 nm and beyond while suppressing effectively short channel effect, and have superior performance compared to 2-dimensional (2-D) MOSFETs. Bulk FinFETs are built on bulk Si wafers which have less defect density and lower cost than SOI(Silicon-On-Insulator) wafers. In contrast to SOI FinFETs, bulk FinFETs have no floating body effect and better heat transfer rate to the substrate while keeping nearly the same scalability. The bulk FinFET has been developed at 14 nm technology node, and applied in mass production of AP and CPU since 2015. In the development of the bulk FinFETs at 10 nm and beyond, self-heating effects (SHE) is becoming important. Accurate control of device geometry and threshold voltage between devices is also important. The random telegraph noise (RTN) would be problematic in scaled FinFET which has narrow fin width and small fin height.

• 반도체디스플레이기술학회지
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• 제14권2호
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• pp.41-45
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• 2015

From 20nm technology node, the finFET has become standard device for ULSI's. However, the finFET process made stacking gate non-volatile memory obsolete. Some reported capacitor-less DRAM structure by utilizing the FBE. We present possible non-volatile memory device structure similar to the dual gate MOSFET. One of the gates is left floating. Since body of the finFET is only 40nm thick, control gate bias can make electron tunneling through the floating gate oxide which sits across the body. For programming, gate is biased to accumulation mode with few volts. Simulation results show that the programming electron current flows at the interface between floating gate oxide and the body. It also shows that the magnitude of the programming current can be easily controlled by the drain voltage. Injected electrons at the floating gate act similar to the body bias which changes the threshold voltage of the device.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권9호
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• pp.1998-2016
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• 2012

Reliable spectrum sensing algorithm is a fundamental component in cognitive radio. In this paper, a non-cooperative spectrum sensing algorithm which needs only one cognitive radio node named CORDIC (Coordinate Rotation Digital Computer) Jacobi based method is proposed. The algorithm computes the eigenvalues of the sampled covariance of received signal mainly by shift and additional operations, which is suitable for hardware implementation. Based the latest random matrix theory (RMT) about the distribution of the limiting maximum and minimum eigenvalue ratio, the relationship between the probability of false alarm and the decision threshold is derived. Simulations and discussions show the method is effective. Real captured digital television (DTV) signals and Universal Software Radio Peripheral (USRP) are also employed to evaluate the performance of the algorithm, which prove the proposed algorithm can be applied in practical spectrum sensing applications.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (D)
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• pp.240-244
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• 2006

무선 센서 네트워크의 노드들은 소형으로써 배터리로 작동하고, 사용자로부터 원거리 또는 산악지대와 같이 배터리 교체가 쉽지 않은 곳에 배치되기 때문에 한정된 에너지를 효율적으로 사용하는 기술이 매우 중요하다. 이를 위해서 같은 지역에 대해 중첩되게 센싱하고 있는 노드들이 있다면 적정한 수의 노드만 활동하게 하고 나머지는 활동하지 않게 함으로써 노드들의 에너지 사용 효율을 높일 수 있다. 본 논문에서는 센서 노드가 유효센싱범위(ESA, Effective Sensing Area)를 계산하여 threshold초과 여부에 따라 working/sleeping하도록 함으로써 중첩되는 센싱범위를 최소화 하고 전체 센싱 커버리지를 유지시키면서 네트워크 수명을 증가시키는 스케줄링 프로토콜을 제안한다.

• 스마트미디어저널
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• 제3권1호
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• pp.28-32
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• 2014

It is practical nowadays to automate data recording in order to prevent loss and tampering of records. There are existing technologies that satisfy this needs and one of them is wireless sensor networks (WSN). Wireless body sensor networks (WBSN) are wireless networks and information-processing systems which are deployed to monitor medical condition of patients. In terms of performance, WBSNs are restricted by energy, and communication between nodes. In this paper, we focused in improving the performance of communication to achieve less energy consumption and to save power. The main idea of this paper is to prioritize nodes that exhibit a sudden change of vital signs that could put the patient at risk. Cluster head is the main focus of this study in order to be effective; its main role is to check the sent data of the patient that exceeds threshold then transfer to the sink node. The proposed scheme implemented added a time-based protocol to sleep/wakeup mechanism for the sensor nodes. We seek to achieve a low energy consumption and significant throughput in this study.