• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1529-1533
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• 2008

The detection characteristics of gamma-irradiated ($0{\sim}10.0\;kGy$) medicinal herbs (Platycodon grandiflorum, Acanthopanax chiisanensis) were investigated by photostimulated luminescence (PSL), thermoluminescence (TL), and electron spin resonance (ESR). The results of the PSL, a first screening method in comparison with the TL, showed photon counts greater than 5,000 counts/60 s (positive) in the irradiated samples, while the non-irradiated samples yielded photon counts less than 700 counts/60 s (negative). The TL was also applied for the detection method of irradiated medicinal herbs and showed that the non-irradiated sample revealed a glow curve with a low intensity, while the irradiated samples showed a higher intensity. These results were normalized by re-irradiating the mineral grains with a irradiation dose of 1.0 kGy, and a second glow curve was recorded. The ratio of the intensity of the first glow curve ($TL_1$) to that after the normalization dose ($TL_2$) was determined and compared with the recommended threshold values. TL ratio ($TL_1/TL_2$) was below 0.007 for the non-irradiated sample and higher than 0.1 for all irradiated samples (above 1.0 kGy). ESR spectroscopy revealed specific signals (6.065 mT) derived from free radicals in cellulose containing irradiated medicinal herbs. The P. grandiflorum showed clearer signals than A. chiisanensis. From the results of our studies, the PSL, TL, and ESR determinations were found to be suitable for the detection of irradiated medicinal herbs such as P. grandiflorum and A. chiisanensis.

• Progress in Medical Physics
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• v.25 no.2
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• pp.65-71
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• 2014

A Varian Portal Dosimetry system was compared to an isocentrically mounted MapCHECK 2 diode array for volumetric modulated arc therapy (VMAT) QA. A Varian TrueBeam STx with an aS-1000 digital imaging panel was used to acquire VMAT QA images for 13 plans using four photon energies (6, 8, 10 and 15 MV). The EPID-based QA images were compared to the Portal Dose Image Prediction calculated in the Varian Eclipse treatment planning system (TPS). An isocentrically mounted Sun Nuclear MapCHECK 2 diode array with 5 cm water-equivalent buildup was also used for the VMAT QAs and the measurements were compared to a composite dose plane from the Eclipse TPS. A ${\gamma}$ test was implemented in the Sun Nuclear Patient software with 10% threshold and absolute comparison at 1%/1 mm (dose difference/distance-to-agreement), 2%/2 mm, and 3%/3 mm criteria for both QA methods. The two-tailed paired Student's t-test was employed to analyze the statistical significance at 95% confidence level. The average ${\gamma}$ passing rates were greater than 95% at 3%/3 mm using both methods for all four energies. The differences in the average passing rates between the two methods were within 1.7% and 1.6% of each other when analyzed at 2%/2 mm and 3%/3 mm, respectively. The EPID passing rates were somewhat better than the MapCHECK 2 when analyzed at 1%/1 mm; the difference was lower for 8 MV and 10 MV. However, the differences were not statistically significant for all criteria and energies (p-values >0.05). The EPID-based QA showed large off-axis over-response and dependence of ${\gamma}$ passing rate on energy, while the MapCHECK 2 was susceptible to the MLC tongue-and-groove effect. The two fluence-based QA techniques can be an alternative tool of VMAT QA to each other, if the limitations of each QA method (mechanical sag, detector response, and detector alignment) are carefully considered.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.1
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• pp.79-84
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• 2013

DC/DC switching power converters are commonly used to generate a regulated DC output voltage with high efficiency. The DC/DC converter is composed of a PWM-IC (pulse width modulation-integrated circuit) controller, a MOSFET (metal-oxide semiconductor field effect transistor), inductor, capacitor, etc. It is shown that the variation of threshold voltage and the offset voltage in the electrical characteristics of PWM-IC increase by radiation effects in TID (Total Ionizing Dose) testing at the low energy ${\gamma}$ rays using $^{60}Co$, and 4 heavy ions applied for SEL (Single Event Latch-up) make the PWM pulse unstable. Also, the output waveform for the given input in the DC/DC converter is observed by the simulation program with integrated circuit emphasis (SPICE). TID testing on PWM-IC is accomplished up to the total dose of 30 krad, and the cross section($cm^2$) versus LET($MeV/mg/cm^2$) in the PWM operation is studied at SEL testing after implementation of the controller board.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.3
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• pp.209-219
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• 2004

In order to implement a real time hardware for keyword spotting, we propose a Single-End-Point DTW(SEP-DTW) algorithm which is simple and less complex for computation. The SEP-DTW algorithm only needs a single end point which enables efficient applications, and it has a small wont of computations because the global search area is divided into successive local search areas. Also, we adopt new local constraints and a new distance measure for a better performance of the SEP-DTW algorithm. Besides, we make a normalization of feature same vectors so that they have the same variance in each frequency bin, and each frame has the same energy levels. To construct several reference patterns for each keyword, we use a clustering algorithm for all training patterns, and mean vectors in every cluster are taken as reference patterns. In order to detect a key word for input streams of speech, we measure the distances between reference patterns and input pattern, and we make a decision whether the distances are smaller than a pre-defined threshold value. With isolated speech recognition and keyword spotting experiments, we verify that the proposed algorithm has a better performance than other methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3641-3655
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• 2016

Wireless sensor networks (WSNs) provide a promising approach to monitor the physical environments, to prolong the network lifetime by exploiting the mutual correlation among sensor readings has become a research focus. In this paper, we design a hierarchical network framework which guarantees layered-compression. Meanwhile, a data sorting-based adaptive spatial compression scheme (DS-ASCS) is proposed to explore the spatial correlation among signals. The proposed scheme reduces the amount of data transmissions and alleviates the network congestion. It also obtains high compression performance by sorting original sensor readings and selectively discarding the small coefficients in transformed matrix. Moreover, the compression ratio of this scheme varies according to the correlation among signals and the value of adaptive threshold, so the proposed scheme is adaptive to various deploying environments. Finally, the simulation results show that the energy of sorted data is more concentrated than the unsorted data, and the proposed scheme achieves higher reconstruction precision and compression ratio as compared with other spatial compression schemes.

• Journal of IKEEE
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• v.20 no.2
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• pp.167-170
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• 2016

Replica bit-line technique is used for making enable signal of sense amplifier which accurately tracks bit-line of SRAM. However, threshold voltage variation in the replica bit-line circuit changes the cell current, which results in variation of the sense amplifier enable time, $T_{SAE}$. The variation of $T_{SAE}$ makes the sensing operation unstable. In this paper, in addition to conventional replica bit-line delay ($RBL_{conv}$), dual replica bit-line delay (DRBD) and multi-stage dual replica bit-line delay (MDRBD) which are used for reducing $T_{SAE}$ variation are briefly introduced, and the maximum possible number of on-cell which can satisfy $6{\sigma}$ sensing yield is determined through simulation at a supply voltage of 0.6V with 14nm FinFET technology. As a result, it is observed that performance of DRBD and MDRBD is improved 24.4% and 48.3% than $RBL_{conv}$ and energy consumption is reduced which 8% and 32.4% than $RBL_{conv}$.

• Smart Structures and Systems
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• v.22 no.5
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• pp.495-508
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• 2018

Shape memory alloys (SMAs) exhibit superelasticity given the ambient temperature is above the austenite finish temperature threshold, the magnitude of which significantly depends on the metal ingredients though. For the monocrystalline CuAlBe SMAs, their superelasticity was found being maintained even when the ambient temperature is down to $-40^{\circ}C$. Thus this makes such SMAs particularly favorable for outdoor seismic applications, such as the framed structures located in cold regions with substantial temperature oscillation. Due to the thermo-mechanical coupling mechanism, the hysteretic properties of SMAs vary with temperature change, primarily including altered material strength and different damping. Thus, this study adopted the monocrystalline CuAlBe SMAs as the kernel component of the SMA braces. To quantify the seismic response characteristics at various temperatures, a wide temperature range from -40 to $40^{\circ}C$ are considered. The middle temperature, $0^{\circ}C$, is artificially selected to be the reference temperature in the performance comparisons, as well the corresponding material properties are used in the seismic design procedure. Both single-degree-of-freedom systems and a six-story braced frame were numerically analyzed by subjecting them to a suite of earthquake ground motions corresponding to the design basis hazard level. To the frame structures, the analytical results show that temperature variation generates minor influence on deformation and energy demands, whereas low temperatures help to reduce acceleration demands. Further, attributed to the excellent superelasticity of the monocrystalline CuAlBe SMAs, the frames successfully maintain recentering capability without leaving residual deformation upon considered earthquakes, even when the temperature is down to $-40^{\circ}C$.

• Journal of Korean Medicine Rehabilitation
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• v.24 no.3
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• pp.111-119
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• 2014

Objectives This study aims to analyze a thermal distribution in biological living tissue during warm needling therapy by using a finite element method. The analysis provides an understanding of warm needling's efficacy and safety. Methods A model which consisted of four-layered tissue and stainless steel needle was adopted to analyze the thermal distribution in living tissue with a bioheat transfer analysis. The governing equation for the analysis was a Pennes' bioheat equation. A heat source characteristic of warm needling therapy was obtained by previous experimental measurements. The first analysis of the time-dependent temperature distribution was conducted through points on a boundary between the needle and the tissue. The second analysis was conducted to visualize the horizontal temperature distribution. Results When heat source's peak temperatures was above $500^{\circ}C$ and temperature rising rates were relatively slow, the peak temperature at skin surface exceeded a threshold of pain and tissue damage ($45^{\circ}C$), whereas when the peak temperature was around $400^{\circ}C$, the peak temperature at the skin surface was within a safe limit. In addition, the conduction of combustion energy from the moxa was limited to the skin layer around the needle. Conclusions The results suggest that the skin layer around the needle can be heated effectively by warm needling therapy, but it appears to have little effect at the deeper tissue. These findings enhance our understanding of the efficacy and the safety of the warm needling therapy.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.5
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• pp.934-944
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• 2011

This study was designed to investigate the effects of Kyungohkgo to improve aerobic capacity and eliminate exercise-induced fatigue in high school soccer players. Twenty four subjects were participated and randomly assigned into two groups [KG, Kyungohkgo group (n=12); PG, Placebo control group (n=12)]. Two groups were completed treadmill exercise protocol using graded exercise test at before and after experimental treatment of 4 weeks. The $VO_2$max and endurance time were measured by gas analysis and heart rate (HR) was measured by polar system at pre, post 0, post 5, post 15, post 30 and post 60 minutes. Blood samples were collected to analyze blood components. 1. The $VO_2$max was significant increased in the group of after intake Kyungohkgo compared to the group of after intake placebo (p<.05). 2. The HR was significant decreased in the group of after intake Kyungohkgo compared to the group of after intake placebo during recovery time at post 5 mins(p<.05), 30 mins(p<.01), 60 mins(p<.01). 3. Weight, body mass index, percent body fat, anaerobic threshold, endurance time, blood lactate concentrate, lactate dyhydrogenase, creatine kinase, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, other energy sources(total-cholesterol, triglyceride, high density lipoprotein-cholesterol, low density lipoprotein-cholesterol, creatinine) and electrolyte (Na, K, Cl) were shown no significant differences between groups. These results suggested that Kyungohkgo can be used as ergogenic aids to improve aerobic capacity and eliminate exercise-induced fatigue.

• Journal of Korea Multimedia Society
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• v.7 no.9
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• pp.1255-1262
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• 2004

This paper proposes a pattern matching algorithm which is useful for pattern matching and verification of images which includes noises. This algorithm is based on the feature that the signal energy of image is concentrated in a small frequency region in Fourier domain. The proposed method extracts the small parts around origins and compares the regions. Specifically, the parts around origins are extracted and subtracted, and finally experimental threshold is adopted for pattern matching. In particular, the proposed algorithm is useful for the images which includes noises because the noises are distributed in the high frequency region generally, and the method extracts the low frequency region only. Experimental result shows the method recognize ten standard images and three images includes various noises. This method shows the performance which is equal to or better than that of Phase Only Correlation in some cases.