• Journal of Photoscience
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• v.9 no.2
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• pp.521-523
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• 2002

5-aminolevulinic acid (ALA) has been used to stimulate endogenous protoporphyrin IX (PpIX) in tumor and then initiate PDT. Recently, ALA-Hexyl ester (He-ALA) was found much effective than ALA on producing PpIX in cancer cells. To clarify the transportation mechanism of ALA and He-ALA, the detection of them is the important step. ALA and its derivatives all don't emit fluorescence, so the Raman spectroscopy was used here for the direct detection of ALA and He-ALA. The results showed that ALA and He-ALA have the common strong Raman peaks at 2930, 2950 CM$\^$-1/, due to the CH$_2$ vibration. The peak 3050 CM$\^$-1/ appeared in ALA spectrum can be attributed to OH vibration, while the peaks of 2860, 2900 CM$\^$-1/ in He-ALA spectrum were assigned as the modes of CH$_3$. This Raman spectral characteristic is consistence with the structure difference of He-ALA and ALA. Thus, Raman spectroscopy provides a new way to detect and distinguish ALA and He-ALA, and could be explored further in biology system.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.6
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• pp.205-212
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• 2015

SSH provides a secure, encrypted communication channel between two end point systems using public key encryption. But SSH brute force attack is one of the most significant attacks. This kind of attack aims to login to the SSH server by continually guessing a large number of user account and password combinations. In this paper, we analyze logs of SSH brute force attacks in 2014 and propose a failed-log based detection mechanism in high performance computing service environment.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1857-1862
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• 2016

Human activity recognition using depth information is an emerging and challenging technology in computer vision due to its considerable attention by many practical applications such as smart home/office system, personal health care and 3D video games. This paper presents a novel framework of 3D human body detection, tracking and recognition from depth video sequences using spatiotemporal features and modified HMM. To detect human silhouette, raw depth data is examined to extract human silhouette by considering spatial continuity and constraints of human motion information. While, frame differentiation is used to track human movements. Features extraction mechanism consists of spatial depth shape features and temporal joints features are used to improve classification performance. Both of these features are fused together to recognize different activities using the modified hidden Markov model (M-HMM). The proposed approach is evaluated on two challenging depth video datasets. Moreover, our system has significant abilities to handle subject's body parts rotation and body parts missing which provide major contributions in human activity recognition.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.125-128
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• 2005

In this paper, we argue that the gigahertz peaked spectrum (GPS) quasars are special blazars, blazars in dense and dusty gas enviornment. The ROSAT detection rate of GPS quasars is similar to that of flat spectrum radio quasars (FSRQs), suggesting that the relativistic jets in GPS quasars are oriented at small angle to the line of sight. Due to strong inverse Compton scattering off infrared photons from dense and dusty nuclear interstellar media in GPS quasars, most of them may have significant soft gamma-ray and X-ray emission, which is consistent with ASCA X-ray observations. Because Compton cooling in GPS quasars is stronger than that in FSRQs, synchrotron emission in GPS quasars may less dominate over thermal emission of the accretion disk and hot dust, hence most GPS quasars show low optical polarization and small variability, consistent with observations. We suggest that it is the significant radio emission of electron/positron pairs produced by the interaction of gamma-rays with the dense gas and dust grains in GPS quasars that makes GPS quasars show steep radio spectra, low radio polarization, and relatively faint VLBI/VLBA cores. Whether GPS quasars are special blazars can be tested by gamma-ray observations with GLAST in the near future, with the detection rate of GPS quasars being similar to that of FSRQs.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.322-328
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• 2005

Acylhomoserine lactones (AHLs) are known to be the triggering molecules in the quorum sensing mechanism of many gram-negative bacteria. In order to detect AHL inhibitors that are potential biofilm inhibitors, a convenient and sensitive bioassay was developed based on the $\beta$-galactosidase activity ($\beta$-GAL) of a recombinant Agrobacterium tumefaciens strain. A series of commercially available AHLs were tested for inducing $\beta$-GAL at varying concentrations in agar-plate and liquid cultures of the reporter strain. All AHLs tested exhibited a concentration­dependent induction, and octanoyl homoserine lactone (OHL) showed the highest sensitivity with a detection limit of 0.1 nM in the liquid culture assay. When fimbrolide, a known quorum sensing inhibitor, was added, induction of $\beta$-GAL by OHL was repressed. The repression at a constant OHL concentration was dependent on the fimbrolide concentration with the detection limit below 1 ppm, indicating that this assay is a sensitive method for screening AHL inhibitors.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.6
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• pp.453-458
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• 2016

CFRP (Carbon Fiber Reinforced Plastic) and CFRP-metal stacks have recently been widely used in the aerospace and automobile industries. When CFRP is machined by a brittle fracture mechanism, defect generation behaviors are different from those associated with metal cutting. The machining quality is strongly dependent on the properties of CFRP materials. Therefore, process control for CFRP machining is necessary to minimize the defects of differently manufactured CFRPs. In this study, defects in drilling of CFRP substrates with a variety of fiber directions and resin types are compared with respect to thrust force. An experimental study on material interface detection is carried out to investigate its benefits in process control.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.3 no.2
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• pp.12-17
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• 2010

An automatic facial feature points(FFPs) detection system is proposed. A face is represented as a graph where the nodes are placed at facial feature points(FFPs) labeled by their Gabor features and the edges are describes their spatial relations. An innovative flexible feature matching is proposed to perform features correspondence between models and the input image. This matching model works likes random diffusion process in the image space by employing the locally competitive and globally corporative mechanism. The system works nicely on the face images under complicated background, pose variations and distorted by facial accessories. We demonstrate the benefits of our approach by its implementation on the system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.705-711
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• 2003

An automatic face and facial feature points(FFPs) detection system is proposed. A face is represented as a graph where the nodes are placed at facial feature points(FFPs) labeled by their Gabor features and the edges are describes their spatial relations. An innovative flexible feature matching is proposed to perform features correspondence between models and the input image. This matching model works likes random diffusion process in !be image space by employing the locally competitive and globally corporative mechanism. The system works nicely on the face images under complicated background, pose variations and distorted by facial accessories. We demonstrate the benefits of our approach by its implementation on the face identification system.

• Smart Structures and Systems
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• v.8 no.1
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• pp.93-105
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• 2011

This paper presents a flexible low-profile antenna sensor for fatigue crack detection and monitoring. The sensor was inspired by the sense of pain in bio-systems as a protection mechanism. Because the antenna sensor does not need wiring for power supply or data transmission, it is an ideal candidate as sensing elements for the implementation of engineering sensor skins with a dense sensor distribution. Based on the principle of microstrip patch antenna, the antenna sensor is essentially an electromagnetic cavity that radiates at certain resonant frequencies. By implementing a metallic structure as the ground plane of the antenna sensor, crack development in the metallic structure due to fatigue loading can be detected from the resonant frequency shift of the antenna sensor. A monostatic microwave radar system was developed to interrogate the antenna sensor remotely. Fabrication and characterization of the antenna sensor for crack monitoring as well as the implementation of the remote interrogation system are presented.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.5
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• pp.419-425
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• 2001

A method to detect lots of porno documents on the internet is presented in this parer. The proposed method applies fuzzy inference mechanism to the conventional information retrieval techniques. First, several example sites on porno arc provided by users and then candidate words representing for porno documents are extracted from theme documents. In this process, lexical analysis and stemming are performed. Then, several values such as tole term frequency(TF), the document frequency(DF), and the Heuristic Information(HI) Is computed for each candidate word. Finally, fuzzy inference is performed with the above three values to weight candidate words. The weights of candidate words arc used to determine whether a liven site is sexual or not. From experiments on small test collection, the proposed method was shown useful to detect the sexual sites automatically.