• Journal of Sensor Science and Technology
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• v.33 no.2
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• pp.112-116
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• 2024

Gas-sensor technology for volatile organic compounds (VOC) biomarker detection offers significant advantages for noninvasive diagnostics, including rapid response time and low operational costs, exhibiting promising potential for disease diagnosis. Colorimetric gas sensors, which enable intuitive analysis of gas concentrations through changes in color, present additional benefits for the development of personal diagnostic kits. However, the traditional method of visually monitoring these sensors can limit quantitative analysis and consistency in detection threshold evaluation, potentially affecting diagnostic accuracy. To address this, we developed a machine vision platform based on metal-organic framework (MOF) for colorimetric gas sensor arrays, designed to accurately detect disease-related VOC biomarkers. This platform integrates a CMOS camera module, gas chamber, and colorimetric MOF sensor jig to quantitatively assess color changes. A specialized machine vision algorithm accurately identifies the color-change Region of Interest (ROI) from the captured images and monitors the color trends. Performance evaluation was conducted through experiments using a platform with four types of low-concentration standard gases. A limit-of-detection (LoD) at 100 ppb level was observed. This approach significantly enhances the potential for non-invasive and accurate disease diagnosis by detecting low-concentration VOC biomarkers and offers a novel diagnostic tool.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.44.1-44.1
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• 2016

The Sagittarius-Carina spiral arm in the Galaxy contains several massive young open clusters. We present a deep optical photometric study on the massive young open clusters in the Sagittarius-Carina arm, Westerlund 2 and the young open clusters in the ${\eta}$ Carina nebula. Westerlund 2 is a less studied starburst-type cluster in the Galaxy. An abnormal reddening law for the intracluster medium of the young starburst-type cluster Westerlund 2 is determined to be $R_{V,cl}=4.14{\pm}0.08$. The distance modulus is determined from zero-age main-sequence fitting to the reddening-corrected color-magnitude diagrams of the early-type members to be $V_0-M_V=13.9{\pm}0.14mag$. The pre-main sequence (PMS) members of Westerlund 2 are selected by identifying the optical counterparts of X-ray emission sources from the Chandra X-ray observation and mid-infrared emission sources from the Spitzer/IRAC (the Infrared Array Camera) observation. The initial mass function (IMF) shows a slightly flat slope of ${\Gamma}=-1.1{\pm}0.1$ down to $5M_{\odot}$. The age of Westerlund 2 is estimated to be. 1.5 Myr from the main-sequence turn-on luminosity and the age distribution of PMS stars. The ${\eta}$ Carina nebula is the best laboratory for the investigation of the Galactic massive stars and low-mass star formation under the influence of numerous massive stars. We have performed deep wide-field CCD photometry of stars in the ${\eta}$ Carina nebula to determine the reddening law, distance, and the IMF of the clusters in the nebula. We present VRI and $H{\alpha}$ photometry of 130,571 stars from the images obtained with the 4m telescope at Cerro Tololo Inter-American Observatory (CTIO). RV,cl in the η Carina nebula gradually decreases from the southern part (~4.5, around Trumpler 14 and Trumpler 16) to the northern part around Trumpler 15 (~3.5). Distance to the young open clusters in the ${\eta}$ Carina nebula is partly revised based on the zero-age main-sequence fitting to the reddening-corrected color-magnitude diagrams (CMDs) and the (semi-) reddening-independent CMDs. We select the PMS members and candidates by identifying the optical counterparts of X-ray sources from the Chandra Carina Complex Survey and mid-infrared excess emission stars from the Spitzer Vela-Carina survey. From the evolutionary stage of massive stars and PMS stars, we obtain that the northern young open cluster Trumpler 15 is distinctively older than the southern young open clusters, Trumpler 14 (${\leq}2.5 Myr$) and Trumpler 16 (2.5-3.5 Myr). The slopes of the IMF of Trumpler 14, Trumpler 15, and Trumpler 16 are determined to be $-1.2{\pm}0.1$, $-1.5{\pm}0.3$, and $-1.1{\pm}0.1$, respectively. Based on the RV,cl of several young open clusters determined in this work and the previous studies of our group, We suggest that higher RV,cl values are commonly found for very young open clusters with the age of < 4 Myr. We also confirm the correlation between the slope of the IMF and the surface mass density of massive stars.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.571-578
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• 2017

Bubbles are generated by the boiling of the cooling water when an accident occurs in the reactor and then in order to measure the void fraction, the Optical Fiber Probe(OFP) and optical camera are used in thermal hydraulic safety research. However, such an optical method is not suitable for measuring the void fraction in a $17{\times}17$ array of fuel rods due to the geometrical limitations. This study was conducted as a preliminary study using x-ray system and various phantoms before applying to rod bundles. Through radiographic and tomographic experiments, the tube voltage of the x-ray generator was 130 kVp and the tube current was 1 mA. In addition, it is possible to measure the hole of 1mm in size visually through the bubble resolution phantom, and it is confirmed that the contrast is relatively decreased in the inside of the freon in the case of the contrast evaluation using the road phantom. However, we could obtain good image without distortion when reconstructing the image. Bubble generation phantom experiments were used to confirm the flow direction of the bubbles and to acquire tomography images. The image J tool was used to measure the void fraction of 18 % for a single tomography image. This study has carried out previous researches for the measurement of the bubble rate around the nuclear fuel and could be used as a basic research for continuous research.

• The Journal of the Korea Contents Association
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• v.16 no.7
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• pp.609-621
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• 2016

A close-up shot, capturing all the fine details of an actor's face by filling up the frame, expresses an actor's performance more realistically than a stage where a living actor performs on. This is because a close-up generates an impact with its specific images and meanings seizing the attention of the audience and conjures up a psychological effect as if an actor's face is directly communicating with the audience at a minimum distance. Therefore, this study analyzed the film to examine the photographic effect and acting effect of close-up shots and recommend the need for acting training thereof. The film was selected since Song Kang-ho, to add more realism to his character acted going back and forth 20 years of age with a special makeup on face, his facial expressions, gestures, props in close-up successfully helped deliver the actor's performance by revealing the character's personality and emotions of the film, and generated an array of linguistic, visual and emotional meanings which are the key to film acting. This study is expected to contribute to helping actors to learn about the effect of close-ups and the key to film acting and find effective ways to express themselves in front of the camera.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.3
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• pp.39-43
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• 2009

In this paper, the flow characteristics of underfill material driven by capillary action between flip-chip and substrate were investigated. Also, the effects of viscosity level and dispensing point of underfill on flow characteristics were investigated. Flip chip package size was $5mm{\times}5mm{\times}0.65^tmm$, the diameter of solder bump was 100 ${\mu}m$, and the pitch was 150 ${\mu}m$. It was full grid area-array type with 1024 I/Os. The glass substrate was used and the gap between the chip and substrate was 50 ${\mu}m$. For the experimental study, three different underfills with different viscous properties($2000{\sim}3700$ cps), and two different types of dispensing methods(center dot and edge dot) were used. The flow characteristics and filling time of underfill were investigated by using CCD camera. The results show that the edge flow was faster than center flow due to the edge effect, which was caused by the resistance of solder bumps. In case of edge dot dispensing type, the filling time was faster due to the large edge effect, compared to center dot dispensing type. Also, it was found that the underfill flow was faster and the filling time decreased as the viscosity level of underfill was decreased.

• Progress in Medical Physics
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• v.8 no.2
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• pp.67-76
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• 1997

We studied optical behavior of scintillation light generated in NaI(TI) crystal using Monte Carlo simulation method. The simulation was performed for the model of NaI(TI) scintillator (size: 60 mm ${\times}$ 60 mm ${\times}$ 6 mm) using an optical tracking code. The sensitivity as a function of surface treatment (Ground, Polished, Metal-0.95RC, Polished-0.98RC, Painted- 0.98RC) of the incident surface of the scintillator was compared. The effects of NaI(TI) scintillator thickness and the refractive index of light guide optically coupling between the NaI(TI) scintillator and photomultiplier tube (PMT) were simulated. We also evaluated intrinsic position resolution of the system by calculating the spread of scintillation light generated. The sensitivities of the system having the surface treatment of Ground, Polished, Metal-0.95RC, Polished-0.98RC and Painted-0.98RC were 70.9％, 73.9％, 78.6％, 80.1％ and 85.2％, respectively, and the surface treatment of Painted-0.98RC allowed the highest sensitivity. As increasing the thickness of scintillation crystal and light guide, the sensitivity of the system was decreased. As the refractive index of light guide increases, the sensitivity was increased. The intrinsic position resolution of the system was estimated to be 1.2 mm in horizontal and vertical directions. In this study, the performance of NaI(TI)-PMT detector system was evaluated using Monte Carlo simulation. Based on the results, we concluded that the NaI(TI)-PMT detector array is a favorable configuration for small gamma camera imaging breast tumor using Tc-99m labeled radiopharmaceuticals.

• Korean Journal of Remote Sensing
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• v.14 no.3
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• pp.213-222
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• 1998

Electro-Optical Camera(EOC) is the main payload of the KOrea Multi-Purpose SATellite(KOMPSAT) with the mission of cartography to build up a digital map of Korean territory including a Digital Terrain Elevation Map(DTEM). This instalment which comprises EOC Sensor Assembly and EOC Electronics Assembly produces the panchromatic images of 6.6 m GSD with a swath wider than 17 km by push-broom scanning and spacecraft body pointing in a visible range of wavelength, 510~730 nm. The high resolution panchromatic image is to be collected for 2 minutes during 98 minutes of orbit cycle covering about 800 km along ground track, over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data storage. The image of 8 bit digitization, which is collected by a full reflective type F8.3 triplet without obscuration, is to be transmitted to Ground Station at a rate less than 25 Mbps. EOC was elaborated to have the performance which meets or surpasses its requirements of design phase. The spectral response, the modulation transfer function, and the uniformity of all the 2592 pixel of CCD of EOC are illustrated as they were measured for the convenience of end-user. The spectral response was measured with respect to each gain setup of EOC and this is expected to give the capability of generating more accurate panchromatic image to the users of EOC data. The modulation transfer function of EOC was measured as greater than 16 % at Nyquist frequency over the entire field of view, which exceeds its requirement of larger than 10 %. The uniformity that shows the relative response of each pixel of CCD was measured at every pixel of the Focal Plane Array of EOC and is illustrated for the data processing.

• Geophysics and Geophysical Exploration
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• v.8 no.4
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• pp.270-279
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• 2005

Under the research project supported by Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), we have conducted the development of GPR systems for landmine detection. Until 2005, we have finished development of two prototype GPR systems, namely ALIS (Advanced Landmine Imaging System) and SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar). ALIS is a novel landmine detection sensor system combined with a metal detector and GPR. This is a hand-held equipment, which has a sensor position tracking system, and can visualize the sensor output in real time. In order to achieve the sensor tracking system, ALIS needs only one CCD camera attached on the sensor handle. The CCD image is superimposed with the GPR and metal detector signal, and the detection and identification of buried targets is quite easy and reliable. Field evaluation test of ALIS was conducted in December 2004 in Afghanistan, and we demonstrated that it can detect buried antipersonnel landmines, and can also discriminate metal fragments from landmines. SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar) is a machine mounted sensor system composed of B GPR and a metal detector. The GPR employs an array antenna for advanced signal processing for better subsurface imaging. SAR-GPR combined with synthetic aperture radar algorithm, can suppress clutter and can image buried objects in strongly inhomogeneous material. SAR-GPR is a stepped frequency radar system, whose RF component is a newly developed compact vector network analyzers. The size of the system is 30cm x 30cm x 30 cm, composed from six Vivaldi antennas and three vector network analyzers. The weight of the system is 17 kg, and it can be mounted on a robotic arm on a small unmanned vehicle. The field test of this system was carried out in March 2005 in Japan.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.27-47
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• 1992

Engineers have developed new instruments that aid in diagnosis and therapy Ultrasonic imaging has provided a nondamaging method of imaging internal organs. A complex transducer emits ultrasonic waves at many angles and reconstructs a map of internal anatomy and also velocities of blood in vessels. Fast computed tomography permits reconstruction of the 3-dimensional anatomy and perfusion of the heart at 20-Hz rates. Positron emission tomography uses certain isotopes that produce positrons that react with electrons to simultaneously emit two gamma rays in opposite directions. It locates the region of origin by using a ring of discrete scintillation detectors, each in electronic coincidence with an opposing detector. In magnetic resonance imaging, the patient is placed in a very strong magnetic field. The precessing of the hydrogen atoms is perturbed by an interrogating field to yield two-dimensional images of soft tissue having exceptional clarity. As an alternative to radiology image processing, film archiving, and retrieval, picture archiving and communication systems (PACS) are being implemented. Images from computed radiography, magnetic resonance imaging (MRI), nuclear medicine, and ultrasound are digitized, transmitted, and stored in computers for retrieval at distributed work stations. In electrical impedance tomography, electrodes are placed around the thorax. 50-kHz current is injected between two electrodes and voltages are measured on all other electrodes. A computer processes the data to yield an image of the resistivity of a 2-dimensional slice of the thorax. During fetal monitoring, a corkscrew electrode is screwed into the fetal scalp to measure the fetal electrocardiogram. Correlations with uterine contractions yield information on the status of the fetus during delivery To measure cardiac output by thermodilution, cold saline is injected into the right atrium. A thermistor in the right pulmonary artery yields temperature measurements, from which we can calculate cardiac output. In impedance cardiography, we measure the changes in electrical impedance as the heart ejects blood into the arteries. Motion artifacts are large, so signal averaging is useful during monitoring. An intraarterial blood gas monitoring system permits monitoring in real time. Light is sent down optical fibers inserted into the radial artery, where it is absorbed by dyes, which reemit the light at a different wavelength. The emitted light travels up optical fibers where an external instrument determines O2, CO2, and pH. Therapeutic devices include the electrosurgical unit. A high-frequency electric arc is drawn between the knife and the tissue. The arc cuts and the heat coagulates, thus preventing blood loss. Hyperthermia has demonstrated antitumor effects in patients in whom all conventional modes of therapy have failed. Methods of raising tumor temperature include focused ultrasound, radio-frequency power through needles, or microwaves. When the heart stops pumping, we use the defibrillator to restore normal pumping. A brief, high-current pulse through the heart synchronizes all cardiac fibers to restore normal rhythm. When the cardiac rhythm is too slow, we implant the cardiac pacemaker. An electrode within the heart stimulates the cardiac muscle to contract at the normal rate. When the cardiac valves are narrowed or leak, we implant an artificial valve. Silicone rubber and Teflon are used for biocompatibility. Artificial hearts powered by pneumatic hoses have been implanted in humans. However, the quality of life gradually degrades, and death ensues. When kidney stones develop, lithotripsy is used. A spark creates a pressure wave, which is focused on the stone and fragments it. The pieces pass out normally. When kidneys fail, the blood is cleansed during hemodialysis. Urea passes through a porous membrane to a dialysate bath to lower its concentration in the blood. The blind are able to read by scanning the Optacon with their fingertips. A camera scans letters and converts them to an array of vibrating pins. The deaf are able to hear using a cochlear implant. A microphone detects sound and divides it into frequency bands. 22 electrodes within the cochlea stimulate the acoustic the acoustic nerve to provide sound patterns. For those who have lost muscle function in the limbs, researchers are implanting electrodes to stimulate the muscle. Sensors in the legs and arms feed back signals to a computer that coordinates the stimulators to provide limb motion. For those with high spinal cord injury, a puff and sip switch can control a computer and permit the disabled person operate the computer and communicate with the outside world.