• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.979-982
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• 2005

• Carbon letters
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• v.10 no.1
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• pp.33-37
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• 2009

Activated carbon (AC) is one of the most effective adsorbents for organic compounds because of their extended surface area, high adsorption capacity, microporous structure and special surface reactivity. The composites of pH-sensitive hydrogel and activated carbon were prepared in order to improve the loading capacity of drug. The pH-sensitive hydrogel matrix swelled well in the basic condition to release the drug loaded in AC. The release of drug was controlled depending on both the pH due to the ionization of the carboxylic acid group and the AC due to the surface properties.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.2
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• pp.8-14
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• 2014

Many kinds of robots and machines have been developed to replace human laborin industrial and medical fields, as well as domestic life. In these applications, the device sneed to obtain environmental data using diverse sensors. Among such sensors, the tactile sensor is important because of its ability to get information regarding surface texture and force through the use of mechanical contact. In this research, a simple tactile sensor was developed using the direct writing of pressure sensitive material and layered fabrication of photocurable material. The body of the sensor was fabricated using layered fabrication, and pressure sensitive materials were dispensed between the layers using direct writing. We examined the line fabrication characteristics of the pressure sensitive material according to nozzle dispensing conditions. A simple $4{\times}4$ array flexible tactile sensor was successfully fabricated using the proposed process.

• Journal of Biomedical Engineering Research
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• v.26 no.1
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• pp.37-42
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• 2005

We construct and test the polarization-sensitive optical coherence tomography (PS-OCT) system for imaging porcine and human articular cartilages. PS-OCT is a new imaging technology that provides information regarding not only the tissue structures but tissue components that show birefringence such as collagen. In this study, we measure the cartilage thickness of the porcine joint and the phase retardation due to collagen birefringence. Also, we demonstrate that changes of the collagen fiber orientation could be detected by the PS-OCT system. Finally, differences between normal and damaged human articular cartilage are observed using the PS-OCT system, which is then compared with the regular histology pictures. As a result, the PS-OCT system is proven to be effective for diagnosis of the pathology related to the cartilage. In the future, this technology may be used for discrimination of the collagen types. When combined with endoscope technologies, the PS-OCT images may become a useful tool for in vivo tissue testing.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.1-9
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• 2021

In this paper, we propose a training algorithm of support vector machine (SVM) with a sensitive variable. Although machine learning models enable automatic decision making in the real world applications, regulations prohibit sensitive information from being used to protect privacy. In particular, the privacy protection of the legally protected attributes such as race, gender, and disability is compulsory. We present an efficient least square SVM (LSSVM) training algorithm using a fully homomorphic encryption (FHE) to protect a partial sensitive attribute. Our framework posits that data owner has both non-sensitive attributes and a sensitive attribute while machine learning service provider (MLSP) can get non-sensitive attributes and an encrypted sensitive attribute. As a result, data owner can obtain the encrypted model parameters without exposing their sensitive information to MLSP. In the inference phase, both non-sensitive attributes and a sensitive attribute are encrypted, and all computations should be conducted on encrypted domain. Through the experiments on real data, we identify that our proposed method enables to implement privacy-preserving sensitive LSSVM with FHE that has comparable performance with the original LSSVM algorithm. In addition, we demonstrate that the efficient sensitive LSSVM with FHE significantly improves the computational cost with a small degradation of performance.

• Journal of the Optical Society of Korea
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• v.10 no.3
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• pp.130-142
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• 2006

Lab-on-a-chip technology is attracting great interest because the miniaturization of reaction systems offers practical advantages over classical bench-top chemical systems. Rapid mixing of the fluids flowing through a microchannel is very important for various applications of microfluidic systems. In addition, highly sensitive on-chip detection techniques are essential for the in situ monitoring of chemical reactions because the detection volume in a channel is extremely small. Recently, a confocal surface enhanced Raman spectroscopic (SERS) technique, for the highly sensitive biological analysis in a microfluidic sensor, has been developed in our research group. Here, a highly precise quantitative measurement can be obtained if continuous flow and homogeneous mixing condition between analytes and silver nano-colloids are maintained. Recently, we also reported a new analytical method of DNA hybridization involving a PDMS microfluidic sensor using fluorescence energy transfer (FRET). This method overcomes many of the drawbacks of microarray chips, such as long hybridization times and inconvenient immobilization procedures. In this paper, our recent applications of the confocal Raman/fluorescence microscopic technology to a highly sensitive lab-on-a-chip detection will be reviewed.

• Journal of Korean Institute of Industrial Engineers
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• v.28 no.1
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• pp.57-62
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• 2002

The semiconductor industry has continuously been looking for the ways to improve yield and to reduce manufacturing cost. The layout modification approach, one of yield enhancement techniques, is applicable to all design styles, but it does not require any additional resources in terms of silicon area. The layout modification method for yield enhancement consists of making local variations in the layout of some layers in such a way that the critical area, and consequently the sensitivity of the layer to point defects, is reduced. Chen and Koren (1995) proposed a greedy algorithm that removes defect sensitive area using via moving, but it is easy to fall into a local minimum. In this paper, we present a via moving algorithm using simulated annealing and enhance yield by diminishing defect sensitive area. As a result, we could decrease the defect sensitive area effectively compared to the greedy algorithm presented by Chen and Koren. We expect that the proposed algorithm can make significant contributions on company profit through yield enhancement.

• Journal of the Korean Applied Science and Technology
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• v.25 no.4
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• pp.525-532
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• 2008

To prepare a solution type acrylic pressure-sensitive adhesive, quarter polymers were synthesized from butyl acrylate(BA), 2-ethylhexylacrylate(2-EHA) as a base monomer, methyl methacrylate(MMA) as a comonomer, each of methacrylic acid(MAA), acrylic acid(AA) as a functional monomer. Acrylic solution type pressure-sensitive adhesives(PSA's) of isocyanate derivative crosslinking PSA's were prepared by crosslinking of BEMM, BEMA with toluene-2,4-diisocyanate. The structure of adhesive was identified by FT-IR. The viscosity was measured by using Brookfield DV-III and molecular weight was measured by using gel permeation chromatography. The physical properties of polyethylene film coated with BEMMT, BEMAT were measured as a function of the concentration. As the result, BEMMT(0.6, 0.8), BEMAT(0.6) showed peel adhesion of $160{\sim}180\;g_f$/25 mm width and shear adhesion of more than 24 hours, and tackiness of $4/32{\sim}6/32$ which was relevant to commercial usage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.939-946
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• 2012

Recently privacy breaches has been an social issues. If we should encrypt the sensitive information in order to protect the database, the leakage of the personal sensitive data will be reduced for sure. In this paper, we analyzed the existing protection algorithms to protect the personal sensitive data and proposed the combined method using the bucket index method and the bloom filters. Bucket index method applied on tuples data encryption method is the most widely used algorithm. But this method has the disadvantages of the data exposure because of the bucket index value presented. So we proposed the combined data encryption method using bucket index and the bloom filter. Features of the proposed scheme are the improved search performance of data as well as the protection of the data exposure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.10a
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• pp.55-60
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• 1994

The paper is aimed at investigating the buckling strength of single-layer latticed domes with the geometrically initial imperfection under the uniformly distributed vertical-loading and the partially concentrated equipment-loading. The results show that the effect of initial imperfection on the buckling strength, if the magnitude of equipment-loading is small, is much more sensitive in domes of overall buckling than in domes of member buckling, but with increasing equipment-loading, it is very sensitive both in domes of overall buckling and of member buckling