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31.
As the use of the computer is popularized, the damage from computer viruses and hacking by malicious users is increasing rapidly.
To block the hacking that is an intrusion into a person's computer, and the viruses that destroy data, a study into an intrusion
detection and virus detection system based on the biological immune system is in progress. In this article, we describe a
model of positive and negative selection for self-recognition, which has a similar function to the cytotoxic T cells that
play an important role in the biological immune system. We propose a self/nonself discrimination algorithm for a computer
system, which will the important when we detect data infected by a computer virus, of data modified by an intrusion from outside.
We also show the validity and effectiveness of the proposed self-recognition algorithm by a computer simulation of some infected
data obtained from cell changes and string changes in the self-file.
This work was presented, in part, at the Seventh International Symposium on Artificial Life and Robotics, Oita, Japan, January
16–18, 2002 相似文献
32.
Robust reweighted MAP motion estimation 总被引:2,自引:0,他引:2
Dong-Gyu Sim Rae-Hong Park 《IEEE transactions on pattern analysis and machine intelligence》1998,20(4):353-365
This paper proposes a motion estimation algorithm that is robust to motion discontinuity and noise. The proposed algorithm is constructed by embedding the least median squares (LMedS) of robust statistics into the maximum a posteriori (MAP) estimator. Difficulties in accurate estimation of the motion field arise from the smoothness constraint and the sensitivity to noise. To cope robustly with these problems, a median operator and the concept of reweighted least squares (RLS) are applied to the MAP motion estimator, resulting in the reweighted robust MAP (RRMAP). The proposed RRMAP motion estimation algorithm is also generalized for multiple image frame cases. Computer simulation with various synthetic image sequences shows that the proposed algorithm reduces errors, compared to three existing robust motion estimation algorithms that are based on M-estimation, total least squares (TLS), and Hough transform. It is also observed that the proposed algorithm is statistically efficient and robust to additive Gaussian noise and impulse noise. Furthermore, the proposed algorithm yields reasonable performance for real image sequences 相似文献
33.
Kwang Mong Sim 《Computational Intelligence》2004,20(4):643-662
The contribution of this work is designing and developing enhanced market-driven agents with the flexibility to (1) respond to changing market conditions, and (2) raise and relax trade aspirations. Previous theoretical analyses have shown that market-driven agents ( MDA s) make prudent compromises by reacting to changing market situations by taking into account factors such as competition, deadlines, and trading options. This work augments the design of an MDA with three fuzzy decision controllers that guide the agent in (i) relaxing trade aspiration in face of intense negotiation pressure, and (ii) raising trade aspiration in extremely favorable markets. Results from extensive simulations conducted using an implemented testbed suggest that when compared to MDA s, agents in this work achieved (1) higher success rates in reaching deals, (2) higher average utilities, and (3) higher expected utility. 相似文献
34.
Jaesu Kim Kwang-Jae Lee Cheul-Ro Lee Mun Seok Jeong Hoonsoo Kang Jin Dong Song Jung Il Lee Sam Kyu Noh Jae-Young Leem 《Thin solid films》2010,518(22):6500-6504
We report the influences of growth parameters on the characteristics of GaAs quantum rings (QRs) and quantum dots (QDs) formed on AlGaAs/GaAs by the droplet epitaxy (DE) method. After forming Ga droplets on the AlGaAs/GaAs surface, varying amounts of arsenic (As) flux were introduced to fabricate the GaAs quantum structures. By decreasing the As flux from 8 × 10− 5 to 3 × 10− 5 Torr, the shape of the GaAs quantum structures was changed from QDs to elongated QRs. With further decreasing As flux, the shape of the elongated QRs became symmetric. The formation characteristics of the GaAs QRs from the QDs with the amount of As flux were discussed in terms of migration behaviors of the gallium (Ga) atoms on the GaAs(001)-c(4 × 4) surface. The effects of the amount of Ga supply and the growth temperature for the deposition of Ga droplets on the formation of the GaAs quantum structures were also considered. 相似文献
35.
V. Senthilkumar ;Le C. Tam ;Yong Soo Kim ;Yumin Sim ;Maeng-Je Seong ;Joon. I. Jang 《Nano Research》2014,(12):1759-1768
There has been growing research interest in the use of molybdenum disulfide in the fields of optoelectronics and energy harvesting devices, by virtue of its indirect-to-direct band gap tunability. However, obtaining large area thin films of MoS2 for future device applications still remains a challenge. In the present study, the amounts of the precursors (S and MOO3) were varied systematically in order to optimize the growth of highly crystalline and large area MoS2 layers by the chemical vapor deposition method. Careful control of the amounts of precursors was found to the key factor in the synthesis of large area highly crystalline flakes. The thickness of the layers was confirmed by Raman spectroscopy and atomic force microscopy. The optical properties and chemical composition were studied by photoluminescence (PL) and X-ray photoelectron spectroscopy. The emergence of strong direct excitonic emissions at 1.82 eV (A-exciton, with a normalized PL intensity of -55 × 10^3) and 1.98 eV (B-exciton, with a normalized PL intensity of -5 × 10^3) of the sample at room temperature clearly indicates the high luminescence quantum efficiency. The mobility of the films was found to be 0.09 cm^2/(V.s) at room temperature. This study provides a method for the controlled synthesis of high-quality two-dimensional (2D) transition metal dichalcogenide materials, useful for applications in nanodevices, optoelectronics and solar energv conversion. 相似文献
36.
A novel uniplanar printed antenna with a total size of 115 × 40 mm2 is proposed for mobile device application. By using an inverted L‐shaped feeding mechanism and a meandered shorting strip, a dual‐band operation with wideband characteristic can be achieved. Here, the lower operating band is able to cover the LTE 700 and GSM 850/900 operations, while the higher operating band allows DCS 1800, PCS 1900, UMTS, and LTE 2300 operations. Furthermore, in order to increase the bandwidth of the higher operating band so that LTE 2500 operation can also be covered, an additional parasitic stub is attached to the feed line to excite a resonant frequency at around 2.72 GHz. Parametric studies via simulation are carried out, and prototype of the proposed antenna is also experimentally investigated to validate the simulated results. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012. 相似文献
37.
Wan Zakiah Wan Ismail Kok Swee Sim 《International journal of imaging systems and technology》2011,21(3):280-289
Image processing requires an excellent image contrast‐enhancement technique to extract useful information invisible to the human or machine vision. Because of the histogram flattening, the widely used conventional histogram equalization image‐enhancing technique suffers from severe brightness changes, rendering it undesirable. Hence, we introduce a contrast‐enhancement dynamic histogram‐equalization algorithm method that generates better output image by preserving the input mean brightness without introducing the unfavorable side effects of checkerboard effect, artefacts, and washed‐out appearance. The first procedure of this technique is; normalizing input histogram and followed by smoothing process. Then, the break point detection process is done to divide the histogram into subhistograms before we can remap the gray level allocation. Lastly, the transformation function of each subhistogram is constructed independently. © 2011 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 21, 280‐289, 2011; 相似文献
38.
Moumita Mukherjee Biswanath Mukherjee Youngill Choi Kyoseung Sim Junghwan Do Seungmoon Pyo 《Synthetic Metals》2010,160(5-6):504-509
We report a copper hexadecafluorophthalocyanine (F16CuPc) based n-type organic field-effect transistor (OFET) with polymeric gate dielectrics with different physical/electrical properties. The gate dielectrics are four types of cross-linked poly(4-vinylphenol) and newly prepared poly(4-phenoxy methyl styrene) and those are characterized based on surface tension, leakage current and capacitance. The performance of F16CuPc OFETs with those gate dielectrics was compared. We found that the composition of the gate dielectrics and the interfacial interaction of F16CuPc with the gate dielectric play a decisive role in the performance of OFETs. The effect of physical/electrical properties, composition and processing condition of the gate dielectrics on the device performance was investigated. 相似文献
39.
Kazushi Yamanaka Noritaka Nakaso Takeshi Fukiura Dong Youn Sim 《Electrical Engineering in Japan》2009,168(1):41-51
A thin beam of waves usually diverges due to diffraction, which is a limitation of any device using such waves. However, a surface acoustic wave (SAW) on a sphere with an appropriate aperture does not diverge but is collimated, realizing ultra‐multiple roundtrips along an equator of the sphere. This effect is caused by the balance between diffraction and focusing on a spherical surface, and it enables realization of high‐performance ball SAW sensors. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(1): 41–51, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20817 相似文献
40.
Myeong Seong Sim Hye Jeong Kim Sang Hee Jo Chun Kim Il Yup Chung 《International journal of molecular sciences》2022,23(7)
Lysophosphatidylserine (LysoPS) is an amphipathic lysophospholipid that mediates a broad spectrum of inflammatory responses through a poorly characterized mechanism. Because LysoPS levels can rise in a variety of pathological conditions, we sought to investigate LysoPS’s potential role in airway epithelial cells that actively participate in lung homeostasis. Here, we report a previously unappreciated function of LysoPS in production of a mucin component, MUC5AC, in the airway epithelial cells. LysoPS stimulated lung epithelial cells to produce MUC5AC via signaling pathways involving TACE, EGFR, and ERK. Specifically, LysoPS- dependent biphasic activation of ERK resulted in TGF-α secretion and strong EGFR phosphorylation leading to MUC5AC production. Collectively, LysoPS induces the expression of MUC5AC via a feedback loop composed of proligand synthesis and its proteolysis by TACE and following autocrine EGFR activation. To our surprise, we were not able to find a role of GPCRs and TLR2, known LyoPS receptors in LysoPS-induced MUC5AC production in airway epithelial cells, suggesting a potential receptor-independent action of LysoPS during inflammation. This study provides new insight into the potential function and mechanism of LysoPS as an emerging lipid mediator in airway inflammation. 相似文献