• The Journal of Korean Institute of Next Generation Computing
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• 제13권1호
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• pp.7-21
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• 2017

Multiple antenna techniques employed in fourth generation mobile communication systems are affected on their performance mostly by transmission environments and antenna configurations. The performance of the indoor LTE(Long-term Evolution) MIMO(multiple input multiple output) has been rigorously evaluated with considering various diversity transmission schemes and propagation conditions in the paper. Specifically, MAC TP(medium access control throughput) and LTE system parameters related to the MIMO technique are analyzed for several indoor propagation conditions. The performance comparison between multiple antenna diversity mode and single antenna mode has been derived as well. The results performed in the paper give the guideline on antenna configurations of polarization diversity in LTE 2×2 MIMO for various indoor channel environments, and possibly are exploited by network operators and antenna manufacturers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권5호
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• pp.1433-1449
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• 2023

In recent years, the rapid development of social networks has led to a rapid increase in the amount of information available on the Internet, which contains a large amount of sensitive information related to pornography, politics, and terrorism. In the aspect of sensitive image detection, the existing machine learning algorithms are confronted with problems such as large model size, long training time, and slow detection speed when auditing and supervising. In order to detect sensitive images more accurately and quickly, this paper proposes a multiclassification sensitive image detection method based on lightweight Convolutional Neural Network. On the basis of the EfficientNet model, this method combines the Ghost Module idea of the GhostNet model and adds the SE channel attention mechanism in the Ghost Module for feature extraction training. The experimental results on the sensitive image data set constructed in this paper show that the accuracy of the proposed method in sensitive information detection is 94.46% higher than that of the similar methods. Then, the model is pruned through an ablation experiment, and the activation function is replaced by Hard-Swish, which reduces the parameters of the original model by 54.67%. Under the condition of ensuring accuracy, the detection time of a single image is reduced from 8.88ms to 6.37ms. The results of the experiment demonstrate that the method put forward has successfully enhanced the precision of identifying multi-class sensitive images, significantly decreased the number of parameters in the model, and achieved higher accuracy than comparable algorithms while using a more lightweight model design.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• 제18권2호
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• pp.37-42
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• 2022

An influence analysis on multiple steam generator tube rupture (mSGTR) followed by an unmitigated station blackout is performed to compare the plant responses according to the number of ruptured u-tubes under the assumption of a total of 10 ruptured u-tubes. In all calculation cases, the transient behaviour of major thermal-hydraulic parameters, such as the discharge flow rate through the ruptured u-tubes, reactor header pressure, and void fraction in the fuel channels is found to be overall similar to that of the base case having a single SG with 10 u-tubes ruptured. Additionally, as the conditions of low-flow coolant with high void fraction in the broken loop continued, causing the degradation of decay heat removal, the peak cladding temperature (PCT) would be expected to exceed the limit criteria for ensuring nuclear fuel integrity. However, despite the same total number of ruptured u-tubes, because of the different connection configuration between the SG and pressurizer, a difference is foud in time between the pressurizer low-level signal and reactor header low-pressure signal, affecting the time to trip the reactor and to reach the PCT limit. The present study is expected to provide the technical basis for the accident management strategy for mSGTR transient conditions of CANDU-6 plants.

• Journal of Korean Society of Archives and Records Management
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• 제23권4호
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• pp.1-24
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• 2023

At present, domestic archives within the realm of performing arts predominantly focus on recording through videos, yet they often lack comprehensive documentation of crucial production processes and content services. Recognizing the contemporary significance of archival content services, this study analyzes the archival content within the national performing arts archives websites of the United Kingdom and the United States, serving as international benchmarks. The findings extrapolate insights and implications to propose enhancements for the Museum of Performing Arts in the National Theater of Korea. The analysis focused mainly on the missions and visions on the websites, examining 107 contents from the UK National Theater, 27 from the United States, and 9 from Korea. The suggested improvements encompass clarifying target users and execution tasks in the mission and vision statements, fostering expert collaborations, incorporating preview features, curating content with a single theme, and organizing a comprehensive list on the National Theater's YouTube channel.

• Proceedings of the Korean Biophysical Society Conference
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• 한국생물물리학회 2003년도 정기총회 및 학술발표회
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• pp.37-37
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• 2003

We have shown the $Ca^{2+}$-activated chloride current is present in cardiac myocyte in rabbit pulmonary vein (Kim et al., 2002). This current amplitude was increased as [N $a^{+}$]$_{i}$ was increased and we suggested this chloride current may be involve in the spontaneous action potential frequency change. Since this current is activated by the increase of intracellular $Ca^{2+}$, we would like to test what is the inducer of the increase of [C $a^{2+}$]$_{i}$ between a L-type $Ca^{2+}$-current or a reverse mode of N $a^{+}$-C $a^{2+}$ exchange current. White rabbit (1.5 kg) was used and anesthetized with Ketamin (100 mg/kg). Pulmonary vein (PV) was isolated and sleeve area between left atrium and PV was dissected. Using collagenase (Worthington 0.7 mg/cc), single cardiac myocytes were isolated. In the presence of 15 mM of N $a^{＋}$, three steps of voltage pulses were applied (holding potential : -40 ㎷, -80 ㎷ for 50 msec, 30 ㎷ for 5 msec, 10 ㎷ steps from -70 ㎷ to 60 ㎷). The inward and outward tail current was activated after brief 5 msec prepulse. The outward tail current was blocked by the removal of extracellular chloride substituted by glucuronic acid or by a chloride channel blocker, 5 mM 9-AC. But the inward tail current was still remained even though the amplitude was decreased. The reversal potentials were changed to the direction of the change of chloride equilibrium potential ( $E_{Cl}$ ) but the shift of equilibrium potential was not enough to match to the theoretical equilibrium potential shift. In the presence of L-type $Ca^{2+}$ channel blocker, nifedipine 1 uM, inward tail currents were greatly reduced but the outward current tail currents were still remained. In the presence of N $a^{+}$-C $a^{2+}$ exchange current blocker, 10 uM KB-R7943, the inward and outward tail currents were blocked almost completely. We tried to test the $Ca^{2+}$sensitivity of the chloride current with various [C $a^{2+}$]$_{i}$ in pipette solution from 100 nM to 1 uM but we failed to activate $Ca^{2＋}$-activated chloride currents even though the cell became contracted in the presence of 1 uM $Ca^{2+}$. From these results, we could conclude that the increase of [C $a^{2+}$]$_{i}$ to activate the outward $Ca^{2+}$-activated chloride current was mainly induced by the activation of the reverse mode of N $a^{+}$-C $a^{2+}$ exchanger, But for the increase of [C $a^{2+}$]$_{i}$ to activate the inward tail current, L-type $Ca^{2+}$ current may be the major provoking current. Since the cytosolic increase of [C $a^{2+}$]$_{i}$ through pipette solution have failed to activate $Ca^{2+}$-activated chloride current, this chloride current may have very low $Ca^{2+}$ sensitivity or a comparmental increase $Ca^{2+}$ such as in subsarcolemmal space may activate the chloride current. Since there are several reports and models that the increase of $Ca^{2+}$ in subsarcolemmal space would be over several to tens of uM, both possibility may be valid together.uM, both possibility may be valid together.

• Journal of Veterinary Clinics
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• 제28권5호
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• pp.497-505
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• 2011

Natural orifice transluminal endoscopic surgery is a newly emerging technique recently, with its many potential advantages in clinical practice. Cholecystectomy by Hybrid NOTES in this work, performed with single working channel endoscope in conjunction with a laparoscopic grasping forceps in dogs, is a "bridge" between laparoscopic procedure and pure NOTES. Three different approaches for cholecystectomy were carried out; transgastric, transcolonic and transvaginal. In all three approaches, abdominal opening was made by a 5 mm trocar, followed by making pneumoperitoneum of 4 mmHg with $CO_2$ insufflator. Transgastric cholecystectomy, single working channel endoscope was advanced to the peritoneal cavity through gastric incision in antral region made by endoscopic needle knife. Endoscope was retroflexed to visualize the gall bladder. Transcolonic access, incision for endoscopic entry was done at right ventral wall of descending colon, 15 cm inside from the anus. Incision in transvaginal access was made at right-ventral region, just caudal to the caudal tubercle. With the simple traction by the laparoscopic grasping forceps, good visualization of surgical field was obtained in all three groups. Cystic duct and artery were ligated with endoclips; for complete gall bladder dissection from liver, L-knife was used. Closure of incision sites were done in transgastric and transcolonic cholecystectomy by endoclips, not in transvaginal approach.

• Journal of the Institute of Electronics and Information Engineers
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• 제52권9호
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• pp.63-73
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• 2015

This work proposes a 2-channel time-interleaved (T-I) 10b 120MS/s pipeline SAR ADC minimizing offset mismatch between channels without any calibration scheme. The proposed ADC employs a 2-channel SAR and T-I topology based on a 2-step pipeline ADC with 4b and 7b in the first and second stage for high conversion rate and low power consumption. Analog circuits such as comparator and residue amplifier are shared between channels to minimize power consumption, chip area, and offset mismatch which limits the ADC linearity in the conventional T-I architecture, without any calibration scheme. The TSPC D flip-flop with a short propagation delay and a small number of transistors is used in the SAR logic instead of the conventional static D flip-flop to achieve high-speed SAR operation as well as low power consumption and chip area. Three separate reference voltage drivers for 4b SAR, 7b SAR circuits and a single residue amplifier prevent undesirable disturbance among the reference voltages due to each different switching operation and minimize gain mismatch between channels. High-frequency clocks with a controllable duty cycle are generated on chip to eliminate the need of external complicated high-frequency clocks for SAR operation. The prototype ADC in a 45nm CMOS technology demonstrates a measured DNL and INL within 0.69LSB and 0.77LSB, with a maximum SNDR and SFDR of 50.9dB and 59.7dB at 120MS/s, respectively. The proposed ADC occupies an active die area of 0.36mm2 and consumes 8.8mW at a 1.1V supply voltage.

• Journal of Broadcast Engineering
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• 제17권4호
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• pp.640-658
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• 2012

One of the existing terrestrial multi-channel DTV service frameworks, called KoreaView, provides four programs, composed of MPEG-2 based one HD video and H.264/AVC based three SD videos within one single 6MHz frequency bandwidth. However the additional 3 SD videos can not provide enough quality due to its reduced spatial resolution and low target bitrates. In this paper, we propose a framework, which is called a terrestrial multi-channel high quality hybrid DTV service, to overcome such a weakness of KoreaView services. In the proposed framework, the three additional SD videos are encoded based on an H.264/SVC Spatial Base layer, which is compliant with H.264/AVC, and are delivered via broadcasting networks. On the other hand, and the corresponding three additional HD videos are encoded based on an H.264/SVC Spatial Enhancement layer, which are transmitted over broadband networks such as Internet, thus allowing the three additional videos for users with better quality of experience. In order to verify the effectiveness of the proposed framework, various experimental results are provided for real video contents being used for DTV services. First, the experimental results show that, when the SD sequences are encoded by the H.264/SVC Spatial Base layer at a target bitrate of 1.5Mbps, the resulting PSNR values are ranged from 34.5dB to 42.9dB, which is a sufficient level of service quality. Also it is noted that 690kbps-8,200kbps are needed for the HD test sequences when they are encoded in the H.264/SVC Spatial Enhancement layer at similar PSNR values for the same HD sequences encoded by MPEG-2 at a target bitrate of 12 Mbps.

• Radiation Oncology Journal
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• 제16권4호
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• pp.367-375
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• 1998

Purpose : Xerostomia is a complication met by almost all patients who have radiotherapy for cancers of head and neck. Many studies for prevention of xerostomia will be necessary. Radiation-induced acute response of salivary glands has been defined as interphase death or apoptosis. Increased intracellular calcium level have an important role in radiation-induced apoptosis. Calcium channel blocker may prevent radiation-induced apoptosis of salivary glands. This study was designed to evaluate the effectiveness of diltiazem known as calcium channel blocker and pentoxifylline with inhibition of inflammatory response on the apoptosis as an acute response of radiation in rat salivary glands. Materials and Methods : Sprague-Dawley rats with about body weight 200-250 g were divided into 5 study groups : control, radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation. The diltiazen and pentoxifylline were injected intraperitoneally 20 mg/kg and 50 mg/kg, 30 and 20 mimute before irradiation. respectively. Irradiation was given with a 4 MV linear accelerator. The 1600 cGy of radiation was delivered in a single fraction through a single anterior portal encompassing the entire neck. After 24 h of irradiation, rats were sacrificed and parotid and submandibular glands were removed and stained with hematoxylin and eosin. The quantification of apoptosis was performed by microscopic examination of stained tissue sections at a magnification of 200X and the percentage of apoptotic cell was calculated. Results : On parotid glands, the percentage of apoptosis by radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation were 1.72$\%$ (8.35/486), 0.64$\%$ (2.9/453), 0.23$\%$ (1.2/516), and 0.28$\%$ (1.1/399), respectively. The apoptosis was markedly reduced in the groups receiving drugs compared with groups receivinge, radiation alone (p<0.05). In serous cell of submandibular glands, the percentages of apoptosis of radiation alone, diltiazem with radiation, pentoxifylline with radiation, and diltiazem and pentoxifylline with radiation were 1.94$\%$ (l1/567), 0.34$\%$ (1.9/554), 0.28$\%$ (1.8/637), and 0.22$\%$ (1.3/601), respectively. In the mucus cell of submandibular glands, the percentages of apoptosis were 0.92$\%$ (5.1/552), 0.41$\%$ (2.5/612), 0.29$\%$ (1.3/455), and 0.18$\%$ (1.0/562), respectively. The apoptosis was markedly reduced in the serous glands (p<0.05), but there was no difference in development of apoptosis in each group of mucus gland. Conclusion : These results suggest that radiation-induced apoptosis of serous cells of salivary glands may be decreased by diltiazem and pentoxifylline administration.

• Journal of the Institute of Electronics and Information Engineers
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• 제54권1호
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• pp.96-110
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• 2017

Most of vehicle detection studies using the existing general lens or wide-angle lens have a blind spot in the rear detection situation, the image is vulnerable to noise and a variety of external environments. In this paper, we propose a method that is detection in harsh external environment with noise, blind spots, etc. First, using a fish-eye lens will help minimize blind spots compared to the wide-angle lens. When angle of the lens is growing because nonlinear radial distortion also increase, calibration was used after initializing and optimizing the distortion constant in order to ensure accuracy. In addition, the original image was analyzed along with calibration to remove fog and calibrate brightness and thereby enable detection even when visibility is obstructed due to light and dark adaptations from foggy situations or sudden changes in illumination. Fog removal generally takes a considerably significant amount of time to calculate. Thus in order to reduce the calculation time, remove the fog used the major fog removal algorithm Dark Channel Prior. While Gamma Correction was used to calibrate brightness, a brightness and contrast evaluation was conducted on the image in order to determine the Gamma Value needed for correction. The evaluation used only a part instead of the entirety of the image in order to reduce the time allotted to calculation. When the brightness and contrast values were calculated, those values were used to decided Gamma value and to correct the entire image. The brightness correction and fog removal were processed in parallel, and the images were registered as a single image to minimize the calculation time needed for all the processes. Then the feature extraction method HOG was used to detect the vehicle in the corrected image. As a result, it took 0.064 seconds per frame to detect the vehicle using image correction as proposed herein, which showed a 7.5% improvement in detection rate compared to the existing vehicle detection method.