• Smart Structures and Systems
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• v.29 no.1
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• pp.181-193
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• 2022

Data-driven structural health monitoring (SHM) of civil infrastructure can be used to continuously assess the state of a structure, allowing preemptive safety measures to be carried out. Long-term monitoring of large-scale civil infrastructure often involves data-collection using a network of numerous sensors of various types. Malfunctioning sensors in the network are common, which can disrupt the condition assessment and even lead to false-negative indications of damage. The overwhelming size of the data collected renders manual approaches to ensure data quality intractable. The task of detecting and classifying an anomaly in the raw data is non-trivial. We propose an approach to automate this task, improving upon the previously developed technique of image-based pre-processing on one-dimensional (1D) data by enriching the features of the neural network input data with multiple channels. In particular, feature engineering is employed to convert the measured time histories into a 3-channel image comprised of (i) the time history, (ii) the spectrogram, and (iii) the probability density function representation of the signal. To demonstrate this approach, a CNN model is designed and trained on a dataset consisting of acceleration records of sensors installed on a long-span bridge, with the goal of fault detection and classification. The effect of imbalance in anomaly patterns observed is studied to better account for unseen test cases. The proposed framework achieves high overall accuracy and recall even when tested on an unseen dataset that is much larger than the samples used for training, offering a viable solution for implementation on full-scale structures where limited labeled-training data is available.

• Korean Journal of Clinical Pharmacy
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• v.32 no.2
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• pp.125-132
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• 2022

Background: Fixed-dose combinations have the advantage of improving patient compliance, but may increase the risk of duplicate prescriptions. As the use of fixed-dose combination antihypertensives increases, it is necessary to investigate the current status of class duplication prescriptions (CDP) in patients taking fixed-dose combination antihypertensives in Korea and to identify factors associated with CDP. Methods: We conducted a retrospective observational study using nationally representative claim data. Hypertensive patients aged 20 years or older taking fixed-dose combination antihypertensives were extracted. Among these patients, patients with CDP were identified. A chi-square test was applied to determine the differences between patients with CDP and non-CDP. The associated factors of CDP were identified through multiple logistic regression. Results: Of the 74,165 patients who were prescribed fixed-dose combination antihypertensives, 426 patients (0.6%) with CDP were identified. The most common antihypertensive class associated with CDP was calcium channel blockers (194 patients, 45.5%), followed by angiotensin II receptor blockers (136 patients, 31.9%). Patients aged 75 years or older (odds ratio [OR] 1.83, 95% confidence interval [CI] 1.02-3.52), chronic kidney disease (OR 4.45, 95% CI 2.15-8.25), chronic heart failure (OR 2.71, 95% CI 1.93-3.72), coronary artery disease (OR 2.22, 95% CI 1.60-3.03) and Medical Aid/Patriots and Veterans Insurance (OR 1.49, 95% CI 1.04-2.07) were significantly associated with increased CDP. Conclusions: The factors associated with CDP were the elderly, comorbidities, and low socioeconomic status. Since CDP can result in negative clinical outcomes, active intervention by the pharmacist is warranted.

• Korean Journal of Veterinary Research
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• v.39 no.5
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• pp.878-895
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• 1999

Ischemic preconditioing (IPC), i.e., a preliminary brief episode of ischemia and reperfusion, has been shown to reduce the cell damage induced by long ischemia and reperfusion. Superoxide radical which is produced during reperfusion after ischemia was recognized as a factor of the ischemic injury and it is dismutated into $H_2O_2$ and $O_2$ by two types of intracellular superoxide dismutase (SOD), Cu,Zn-SOD in cytoplasm and Mn-SOD in mitochondria. Recently oxygen free radicals are suggested to induce the apoptosis, however mechanism of the reduced apoptosis by ischemic preconditioing was unknown, while many studies performed in mammalian heart indicated that ATP-sensitive $K^+$ ($K_{APT}$) channel activation related with the protective effects. The aim of present study is to investigate 1) whether IP upregulate the Cu,Zn-SOD and Mn-SOD activities, and 2) whether ischemic preconditioning decreases apoptosis via $K_{APT}$ channel activation in timely reperfused skeletal muscle after long ishemia. The experimental animals, Sprague-Dawley rats weighing 250~300g, were divided into 8 groups; 1) control group, 2) ischemic preconditioning only groups, 3) pinacidil, a $K_{APT}$ channel opener, treatment only groups, 4) glibenclamide, a $K_{APT}$ channel blocker, treatment only groups, 5) ischemia groups, 6) ischemia after IPC groups, 7) ischemia and pinacidil treatment groups, and 8) IP and ischemia after glibenclamide pretreatment groups. Animals of the control group were administered with the vehicle (DMSO) alone. Pinacidil (1mg/kg) was administered intravenously 5 minutes after initiation of ischemia, and glibenclamide (0.5mg/kg) was injected intravenously 20 minutes before IPC. In rats that were ischemic preconditioned, the left common iliac artery was occluded for 5 minutes followed by 5 minutes of reperfusion by three times using vascular clamp. Ischemia was done by occlusion of the same artery for 4 hours. The specimens of left rectus femoris muscle were obtained immediately (0 hour), 12 hours, 24 hours after drug administrations, IP or ischemia and reperfusion. The immunoreactivities of SOD and its alterations were observed by use of sheep antihuman Cu,Zn-SOD and Mn-SOD antibodies on the $10{\mu}m$ cryosections. The incidencies of apoptosis were observed by TUNEL methods with in situ apoptosis detection kit on $6{\mu}m$ paraffine section. The results obtained were as follows : 1. After IPC, immunoreactivities of Cu,Zn-SOD mainly in the small-sized fibers were increased by 24 hours, that of Mn-SOD at 0 hour and 24 hours. 2. No significant changes in immunoreactivities of SOD was observed in the pinacidil and in the glibenclamide treatment only groups, and in the ischemia only groups. 3. The immunoreactivities of the Cu,Zn-SOD were increased in the ischemia after IPC groups and the ischemia and pinacidil treatment groups. 4. The immunoreactivities of the Cu,Zn-SOD in the IPC and ischemia after glibenclamide pretreatment groups were not increased except for the 12 hours reperfusion group. But, Mn-SOD immunoreactivities were increased in the 0 hours, 12 hours and 24 hours after reperfusion. 5. In the control group, the IPC only groups, and the pinacidil treatment only groups, negative or trace apoptotic reactions were observed, but the positive apoptotic reaction occured in the glibenclamide treatment groups. 6. Moderate or many number of apoptosis were revealed in the ischemia groups, and also the IPC and ischemia after glibenclamide pretreatment group except for 12 hours and 24 hours after reperfusion. However, the incidence of apoptosis was decreased in the ischemia after IPC groups and in the ischemia and pinacidil treatment groups. 7. There is a coincidence between the increase of Cu,Zn-SOD immunoreactivities and the decrease of apoptosis in the presence of ischemia and reperfusion. These results suggest that the protective effects of ishemic preconditioing may related to the SOD activation, and the ischemic preconditioning decreases the apoptosis partially via $K_{APT}$ channel activation in timely reperfused rat skeletal muscle. It is also suggested that inhibition of apoptosis by IPC may related with the SOD activation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.251-259
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• 2014

In this paper, we propose Low Energy Service Discovery (LESD) protocol for common discovery mode of IEEE 802.15.8 Peer Aware Communications (PAC). In order to minimize power consumption, Basic Repetition Block (BRB) is defined. Device is able to select operating mode and synchronize other devices through it. Proposed MAC procedure is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) based on overhearing technique. Even if device has not been received response signal since transmitted request signal, it is able to discover other devices of same group through the overhearing technique. IEEE 802.15.8 PAC has required that performances of common discovery mode are presented about discovered devices during the simulation time, discovery latency and average power consumption. By considering the number of devices per group and channel environment, two scenarios are evaluated through system level simulation and the simulation results of proposed scheme are compared with CSMA/CA in same simulation conditions. As a result, proposed scheme is able to get high energy efficiency of devices as well as increase the number of discovered devices during simulation time when the longer the number of devices is distributed over a limited area.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.244-250
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• 2012

This paper describes a 4-Gb/s receiver circuit for a low-swing ground-referenced differential signaling system. The receiver employs a common-gate level-shifter and a continuous linear equalizer which compensates inter-symbol-interference (ISI) and improves voltage and timing margins. A bias circuit maintains the bias current of the level-shifter when the common level of the input signal changes. The receiver is implemented with a low-power 65-nm CMOS technology. When 4-Gb/s 400mVp-p signals are transmitted to the receiver through the channel with the attenuation of -19.7dB, the timing margin based on bit error rate (BER) of $10^{-11}$ is 0.48UI and the power consumption is as low as 0.30mW/Gb/s.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.479-484
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• 2005

Raynaud's syndrome causes discolorization, ischemic claudication(pain) and necrosis of the digits through insufficiency in the circulation which is induced by intermittent spasms of the digital arteries. From January, 2002 to December, 2004, 10 patients were surgically treated for Raynaud's syndrome. 9 patients were female and 1 patient was male. 2 patients showed unilateral involvement, 8 patients were operated on both hands. 6 patients had necrotic changes on the finger tips due to the disease. Ages ranged from 21 to 60 with an average of 39.1. Ischemic pain, discolorization, and cold intolerance of the digits were the common symptoms. All patients were evaluated with color doppler before the surgery. Two different procedures were applied according to the severity of the disease: Patients with decreased circulation received, what we call a limited digital sympathectomy, i.e. stripping of the adventitia of the ulnar, radial and common digital arteries. An extended procedure, radical digital sympathectomy, was performed on patients with a complete block of circulation. Stripping of the adventitia in these patients also involved the proper digital arteries. Symptoms like discolorization, ischemic pain, and cold intolerance improved immediately after the surgery. The patients did not suffer from pain even with exposure to cold weather. We conclude that digital sympathectomy could improve the symptoms in Raynaud's patients who do not respond to conservative treatment such as calcium channel blocker and other vasodilators.

• Journal of Broadcast Engineering
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• v.8 no.3
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• pp.250-258
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• 2003

Recently, the transition from conventional analog broadcasting to digital broadcasting has been proceeding as a result of the advance in digital multimedia broadcasting technique. In radio broadcasting, Eureka-147 DAB(Digital Audio Broadcasting) was decided as the standard system of digital radio broadcasting in Korea. In addition to CD quality audio, a variety of data services and excellent performance in mobile reception can be served by DAB, and DAB was evolved into DMB(Digital Multimedia Broadcasting) in Korea for the purpose of emphasizing moving picture multimedia service by DAB. In case of digital broadcasting, it is absolutely essential to measure the BER(Bit Error Rate) in the received signal in order to evaluate the coverage obtained by a transmitter and the quality of the received signal. In this paper, we propose efficient subchannel data structure and BER measurement algorithm. and then verify it by laboratory experiments. With a proposed method, the synchronization for BER measurement is easily obtained and especially the exact results can be obtained by classifying the lost bits which are included in the reception-failed CIFs(Common Interleaved Frame) into errors. This makes the proposed BER measurement system especially appropriate to DMB in which the frequent changes in channel status caused by mobile reception environment exist.

• The Journal of the Korea Contents Association
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• v.20 no.5
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• pp.513-524
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• 2020

Recently, YouTube's growth started drawing attention. YouTube is not only a content-consumption channel but also provides a space for consumers to express their intention. Consumers share their opinions on YouTube through comments. The study focuses on the text of global entrepreneurs' speeches and the comments in response to those speeches on YouTube. A content analysis was conducted for each speech and comment using the text mining software Leximancer. We analyzed the theme of each entrepreneurial speech and derived topics related to the propensity and characteristics of individual entrepreneurs. In the comments, we found the theme of money, work and need to be common regardless of the content of each speech. Talking into account the different lengths of text, we additionally performed a Prominence Index analysis. We derived time, future, better, best, change, life, business, and need as common keywords for speech contents and viewer comments. Users who watched an entrepreneur's speech on YouTube responded equally to the topics of life, time, future, customer needs, and positive change.

• 전자공학회논문지 IE
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• v.47 no.4
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• pp.53-58
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• 2010

In this paper we propose symbol decision method reflecting the color non-uniformity in 3-dimensional color space. By comparing with 2-dimensional color space decision method, we show the superiority of BER performance of the proposed method. Proposed method may reflect the non-uniformity since the symbol decision boundary in color space is transformed from 3D RGB space, and one dimension corresponding to Y value is added. Therefore, we can obtain the better BER performance by using the symbol decision method in 3D color space. In this paper, through numerical simulation, show the superior BER performance of 3D color space symbol decision method compared with 2D color space symbol decision method under AWGN and common mode noise channel.

• Journal of Internet Computing and Services
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• v.13 no.6
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• pp.25-32
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• 2012

There is a growing controversy on whether and how to regulate real-time broadcasting services carried on smartphone. Some advocates strict regulation on them but the others minimal regulation. This study aims to suggest guiding rules for how to regulate broadcasting services in smartphone. For this, the study interviewed fourteen (14) executives of broadcasting companies, content providers, policy research center and regulatory body. The analysis indicates that linear channel service in smartphone is similar in form to traditional broadcasting but they should not be regulated at this moment. The supporting reasons are 1) regulating them is technically not effective, 2) they were already regulated in their primary service platforms, 3) they don't have a significant impact on a society. Consequently, the study suggests that the service providers are categorized as value added common carriers as defined in the Telecommunication Business Act.