• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.4
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• pp.15-20
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• 2009

In a detection system based on laser light scattering, focusing an excitation laser beam into a focal point of a channel in a microfluidic chip is important for obtaining the highest excitation intensity, and consequently for obtaining a laser light scattering signal using a photodetector with a high efficiency. In this paper, we present a polydimethylsiloxane (PDMS) microfluidic chip consisting of an integrated PDMS microlens for cell detection based on laser light scattering. We fabricated PDMS microlens for optical detection system by simply putting down on PDMS chips. The PDMS microlens was fabricated by photoresist reflow and replica molding. This fabrication technique is simple and has an excellent property in terms of the microlens and a high-dimensional accuracy. The PDMS microlens integrated on the PDMS microfluidic chip has been verified to improve the laser intensity, and accordingly, the signal-to-noise ratio and sensitivity of laser light scattering detection for red blood cells(RBCs)

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.3
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• pp.36-42
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• 2015

The aspherical lens was designed to be able to array a focal point. For this reason, it has very curved surface. The aspherical lens is fabricated by injection molding or diamond turning machine. With the aspherical lens, tool marks and surface roughness affect the optical characteristics, such as transmissivity. However, it is difficult to polish free form surface shapes uniformly with conventional methods. Therefore, in this paper, the ultra-precision polishing method with MR fluid was used to polish an aspherical lens with 4-axis position control systems. A Tool path and polishing mechanism were developed to polish the aspherical lens shape. An MR polishing experiment was performed using a generated tool path with a PMMA aspherical lens after the turning process. As a result, surface roughness was improved from $R_a=40.99nm$, $R_{max}=357.1nm$ to $R_a=4.54nm$, $R_{max}=35.72nm$. Finally, the MR polishing system can be applied to the finishing process of fabrication of the aspherical lens.

• Journal of Forest and Environmental Science
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• v.34 no.4
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• pp.293-303
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• 2018

Sumber Jaya (54,194 hectares) is a district in West Lampung, Indonesia, located at the upper part of Tulang Bawang watershed. This watershed is one major water resource for Lampung Province, but has become a focal point of discussion because of the widespread conversion of forestland to coffee plantations and human settlements which lead to environmental and hydrological problems. This research aimed to evaluate Sumber Jaya watershed affecting by rapid land use change using hydrological methods as a base for watershed management. Nested catchment structure consisted of eight sub-catchments was employed in this research to assess scaling issues of land use change impacts on rainfall-runoff connections. Six tipping bucket rain gages were installed on the hill slopes of each sub-catchment and Parshall flumes were installed at the outlets of each sub-catchment to monitor stream flow. First, unit hydrograph that expressed the relationship of rainfall and runoff was computed using IHACRES model. Second, unit hydrograph was also constructed from observations of input and response during several significant storms with approximately equal duration. The result showed that most of the storm flow from these catchments consisted of slow flow. A maximum of about 50% of the effective rainfall became quick flow, and only less than 10% of remaining effective rainfall which was routed as slow flow contributed to hydrograph peaks; the rest was stored. Also, comparing peak responses and recession rates on the hydrograph, storm flow discharge was generally increased slowly on the rising limb and decreased rapidly on the falling limb. These responses indicated the soils in these catchments were still able to hold and store rain water.

• Journal of the Korea Society of Computer and Information
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• v.16 no.10
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• pp.229-239
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• 2011

This study aims to suggest profitability models of local cultural festival to be a focal point of local culture to overcome the abuses as an annual event led by the local government agencies have been in force in every local areas currently, to elicit the local residents' voluntary participation and to engage the outside tourists in connection of a more effective promotion and marketing. The festival is attractive to people with that provoke mirth and inspire curiosity, but the festival is not a one-time event ongoing maintenance enlarge: It is absolutely necessary in order to effort to reach at consumer-oriented quality of service. Also this research intends to present a activation scheme by developing profitability models to make profits while holding a number of risks taking into account the characteristics of the local festival service carried out. To this end, based on established research, leading indicator and expert opinion were analyzed through multiple regression analysis.

• Korean Journal of Optics and Photonics
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• v.7 no.1
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• pp.51-59
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• 1996

In this paper, we propose a new type of a planar waveguide lens, a meniscus lens instead of a plano-convex lens used widely for the optical integrated circuits such as optical numerical processors. A plano-convex lens has a spherical aberration caused by the linear boundary. In the proposed meniscus lens, this linear boundary is replaced by a circular-boundary, and the spherical aberration is removed. To test the performance of the proposed lens, a meniscus lens is designed using Fermat principle and fabricated on the Y-cut $LiNbO_3$ substrate. First a $Ti:LiNbO_3$ planar waveguide is fabricated on the $LiNbO_3$ substrate by Ti indiffusion. Then a meniscus lens is fabricated on the planar waveguide by TIPE(Ti indiffued proton-exchange) method. A plano-convex lens is also fabricated on the same substrate to compare the spot size at the focal point. The measured spot size of the meniscus lens is reduced to 59% that of the plano-convex lens. This result shows that the proposed meniscus lens is more effective for optical integrated circuits than the plano-convex lens.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.2
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• pp.134-140
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• 2015

Traditional moxibustion therapy can cause severe pain and leave scarring burns at the moxibustion site as it relies on the practitioner's subjective and qualitative treatment. Recently, ultrasound therapy has received attention as an alternative to moxibustion therapy owing to its objectiveness and quantitative nature. However, in order to convert ultrasound energy into heat energy, there is a need to precisely understand the ultrasound-focusing characteristics of the acoustic lens. Therefore, in this study, an FEM simulation was performed for acoustic lenses with different geometries a concave lens and zone lens as the geometry critically influences ultrasound focusing. The acoustic pressure field, amplitude, and focal point were also calculated. Furthermore, the performance of the fabricated acoustic lens was verified by a sound pressure measurement experiment.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.76.1-76.1
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• 2010

With advancement of infrared space telescopes during the past decade, infrared wavelength regime has been a focal point to study various properties of galaxies, such as stellar mass, dust contents and dust-hidden star formation with respect to evolution of galaxies. Polycyclic Aromatic Hydrocarbons (PAHs) have emerged as one of the most important features since these features dominate mid-infrared spectra of galaxies. These PAH features provide a great handle to calibrate star formation rates and diagnose ionized states of grains. However, PAH $3.3{\mu}m$ feature has not been studied as much as other PAH features since it is weaker than others and resides outside of Spitzer's capability. Still its calibration and characterization are important since it will be the only PAH feature accessible by JWST for high-z galaxies. AKARI mJy Unbiased Survey of Extragalactic Sources in 5MUSES (AMUSES) intends to take advantage of AKARI's capability of spectroscopy on 2 to 5 ${\mu}m$ to provide an unbiased library of 44 sample galaxies selected from a parent sample of 5MUSES, one of Spitzer legacy projects. For these 3.3mm flux limited sample galaxies whose redshifts range between 0 < z <1, AMUSES will calibrate PAH $3.3{\mu}m$ as a SFR while measuring ratios between PAH features and investigating Bra's potential as a SFR indicator. We present preliminary results of AMUSES.

• Journal of the Korean Society for information Management
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• v.25 no.3
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• pp.209-230
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• 2008

This study is based on the practical use for distributed resources considering growing network rapidly. The focal point of this study will be argued on semantic interoperability for sharing of resources, not be emphasized the technical issues of network. The aim of this article is developing the model of Collection-Level Description(CLD) for sharing of resources. The present article consists of a definition of collection in relation to the scope, objectives, and agents of the collection and an analysis of researches about CLD strengths and standards. Lastly, it was intended to construct the model focused on relation which was needed to be strengthened the existing CLD's function, thus, this study attempted to use the concept of ontology. The model of CLD based on ontology suggested the description could represent new relations inferred between classes and properties. Distinguishing class and property, furthermore, this study suggested properties were separated the characteristic of class and the relation with classes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.2
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• pp.173-180
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• 2012

The most recent, 80 mega pixels digital camera appeared through the development of digital technology, and nonmetric digital cameras have been using in various field of photogrammetry. In this study, we experimented lens calibration using aerial photographs and ground control points. The aerial photographs were taken a non-metric digital camera which is CMOS(Complementary Metal Oxide Semiconductor) 21.1 mega pixels sensor and 35mm lens at a helicopter. And the ground control points were selected on the 1:1,000 plotting origin data. As a result, we calculated focal length, PPA(Principal Point of Autocollimation) and symmetric radial distortion coefficients from the lens. Also, RMSE(root mean square error) and maximum residual of the ground control points from the aerial triangulation were compared before and after calibration. And we found that the accuracy of the after calibration was improved very significantly.

• Journal of Sensor Science and Technology
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• v.27 no.1
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• pp.47-54
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• 2018

In this paper, we describe the thermal characteristics of the output voltages of ethanol gas sensor according to the amount of radiation incident on the infrared sensors located at each focal point of two elliptical waveguides. In order to verify the output characteristics of the gas sensor according to the amount of incident light on the infrared sensor, two combinations of sensor modules were fabricated. Hydrophobic thin film is deposited on one of the reflectors of sensor modules and one of the two infrared sensors was equipped with a hollow disk (10 Ø), and the temperature characteristics of the infrared sensor equipped with the hollow disk (10 Ø) and the infrared sensor without the disk were tested. The temperature was varied from 253 K to 333 K at 10 K intervals based on 298 K. The properties of ethanol gas sensor have been identified with respect to varying temperature for a range of ethanol concentration from 0 ppm to 500 ppm. In the case of an infrared sensor equipped with a hollow disk (10 Ø), the output voltage of the sensor decreased by 0.8 mV and 1 mV, respectively, as the temperature increased. Conversely, the output voltage of the diskless infrared sensor showed an average increase of 67 mV and 57 mV as the temperature increased. The ethanol concentrations estimated on the basis of results show an error of more than 10 % for less than 100 ppm concentration. However, if the ethanol concentration exceeds 100 ppm, the gas concentration can be estimated within the range of ${\pm}10%$.