• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1887-1894
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• 2016

In the RFID system, the reader transmits a query message to tags in order to identify a unique ID of tags within its detection range. The procedures for arbitrating a collision is essential because the multiple tags can response simultaneously in the same to the query of the Reader. This procedure is known as conflict resolution algorithm and it is a key technology in the RFID system. In this paper, we proposed a variable bits M-ary QT algorithm based on Manchester coding techniques. The proposed algorithm use the location information of the collision bits in the reader and tags. The proposed algorithm can reduce the number of the query-response cycle because it is capable of recognizing discontinuous bits and a variable number of bits. From computer simulation, the proposed method give better performance than the conventional M-ary QT techniques in terms of response, recognition efficiency, communication overhead.

• Korean Journal of Biological Psychiatry
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• v.17 no.1
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• pp.44-48
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• 2010

Objectives : Social phobia is frequently accompanied with autonomic nerve system symptoms. QT dispersion(QTd) is the maximum inter-lead difference in QT interval, an indicator of the autonomic nerve system(ANS) disparity of the heart itself. The objective of this study is to investigate the ANS disparity, which is measured by QTd, is associated with pathophysiology of social phobia. Methods : This research have compared QT dispersion of 25 physically healthy social phobia outpatients(16 men, 9 women, the average age $35.5{\pm}12.9$) and age and sex matched control group of mentally and physically healthy 25 volunteers(16 men, 9 women, the average age $34.83{\pm}12.7$). QTd was measured by previously described method. Results : QTd and rate-corrected QTd were significantly higher on the patient group than the control group[QTd(patients vs. controls : $52.60{\pm}27.63ms$ vs. $27.53{\pm}14.29ms$, p<0.0001), QTd(patients vs. controls : $55.79{\pm}27.98ms$ vs. $29.10{\pm}14.24ms$, p<0.0001)]. Conclusion : Our study showed that the patients with social phobia have higher QTd than the normal controls. These results suggest that the ANS disparity, which is measured by QTd, is associated with pathophysiology of social phobia.

• Journal of Internet Computing and Services
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• v.10 no.2
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• pp.133-141
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• 2009

A tag collision problem occurs when many tags are placed in a interrogation zone in RFID system. A tag collision problem is one of core issues and various protocols have been proposed to solve the collision problems. Generally tree-based protocols generate unique prefixes and identify tags with them as quick as possible. In this paper, we propose the QT-BCS protocol which decreases the identification time by reducing the number of query-response. The QT-BCS protocol makes a prefixes using time slot and bit change sensing unit. This protocol compares the current bit of tags until the current bit is differ from the previous one. When this occurs, all of the bits scanned so far are transferred to slot-0 and slot-1 depending on the first bit value in Reader. Consequently, this method can reduce the number of queries by tracing prefixes easily. Simulation result shows QT-BCS is more efficient in identifying tags than Query Tree and 4-ary Query Tree protocol.

• Communications of Mathematical Education
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• v.36 no.1
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• pp.23-38
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• 2022

The study provided a perspective on which readers can see Newton's proof heuristically in order to overcome the difficulty of proof showing 'QT²/QR converges to the latus rectum of ellipse' in the proof of the inverse square law of Newton's Principia. The heuristic perspective is as follows: The starting point of the proof is the belief that if we transform the denominators and numerators of QT²/QR into expression with respect to segments related to diameter and conjugate diameter, we may obtain some constant, the desired value, by their relationship PV × VG/QV² = PC²/CD² in Apollonius' Conic sections. The heuristic perspective proposed in this study is meaningful because it can help readers understand Newton's proof more easily by presenting the direction of transformation of QT²/QR.

• Clinical and Experimental Pediatrics
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• v.46 no.10
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• pp.996-1002
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• 2003

Purpose : In Rett syndrome patients, the incidence of sudden death is greater than that of the general population, and cardiac electrical instability including fatal cardiac arrhythmia is a main suspected cause. In this study, we are going to find out the possible cause of the higher risk of sudden death in Rett patients by the evaluation of heart rate variability, a marker of cardiac autonomic activity and corrected QT intervals. Methods : Diagnosis of Rett syndrome was made by molecular genetic study of Rett syndrome (MECP2 gene) or clinical diagnostic criteria of Rett syndrome. Heart rate variability and corrected QT intervals were measured by 24 h-Holter study in 12 Rett patients, and in 30 age-matched healthy children with chief complaints of chest pain or suspected heart murmurs. The were compared with the normal age-matched control. Results : Patients with total Rett syndrome, classic Rett syndrome, and Rett variants had significantly lower heart rate variability(especially rMSSD)(P<0.05) and longer corrected QT intervals than age-matched healthy children(P<0.05). Sympathovagal balance expressed by the ratio of high to low frequency(LF/HF ratio) also showed statistically significant differences between the three groups considered(P<0.05). Conclusion : A significant reduction of heart rate variability, a marker of autonomic disarray, suggests a possible explanation of cardiac dysfunction in sudden death associated with Rett syndrome.

• Advances in Traditional Medicine
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• v.3 no.4
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• pp.212-216
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• 2003

This study assessed the effects of Qi therapy (QT) on premenstrual symptoms in women with premenstrual syndrome (PMS). Forty-six college women were randomly allocated to receive QT (QT group: n=23) or complete diary of PMS (control group: n=22, 1 was dropped out). The experimental group receives 12 minutes Qi therapy for 5 times (7, 4, 1 day before and 7, 14 day after menstruation), and control group relaxed in the same procedure with experimental group. We measured pain, depression and anxiety level with visual analogue scale (VAS) to investigate participants responses. There were significant reductions on pain, depression and anxiety in QT group compared with control. These findings suggest that Qi therapy may have a role in helping the women with PMS to cope with their pain, depression and anxiety symptoms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.565-568
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• 2005

RFID system allows contactless identification of objects, where small tags are attached to objects and information of objects are transferred using radio frequency. In recent years, industries have incorporated several identification systems to its production processes, which allow collecting automatically information about goods. In order to communicate with a single tag out of a group of tags, the target tag has to be identified. Therefore the read has to attempt to obtain the unique identification code of each tag within its read range. This paper presents performance results of QT and QT-sl protocols, which are tag identification protocols incorporating memoryless property. The memoryless property is that the current response of each tag only depends on the current query of the reader but not on the past history of the reader's queries.

• Journal of Dental Anesthesia and Pain Medicine
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• v.15 no.3
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• pp.161-165
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• 2015

Long QT syndrome (LQTs) is a rare congenital disorder of the heart's electrical activity. Patients with LQTs are at increased risk of developing fatal ventricular arrhythmias. Elevated levels of sympathetic stimulation can exacerbate this risk. Successful behavior management is indispensable in the treatment of patients with LQTs. However, many drugs involved in pharmacologic behavior management are known to adversely affect the QT interval. Therefore, careful selection of a sedative drug is essential in avoiding such incidences. A 10-year-old boy with a known diagnosis of LQTs required restorative treatment due to dental caries at the permanent molar. He required sedation since treatment was painful and dental phobia can trigger sympathetic stimulation, creating a dangerous situation for patients with LQTs. Therefore, the treatment was performed over two sessions under moderate sedation involving propofol combined with nitrous oxide. Restorative treatment was successful without any complications under sedation with a target-controlled infusion (TCI) of propofol. There was no significant QT prolongation during pulpal treatment. Propofol TCI may be a good candidate for sedation in patients with LQTs.

• Journal of Internet of Things and Convergence
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• v.2 no.3
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• pp.43-51
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• 2016

In this paper, we have developed Crypft+ as an enhanced file encryption/decryption system to improve the security of IoT system or individual document file management process. The Crypft+ system was developed as a core security module using Python, and designed and implemented a user interface using PyQt. We also implemented encryption and decryption function of important files stored in the computer system using AES based symmetric key encryption algorithm and SHA-512 based hash algorithm. In addition, Cx-Freezes module is used to convert the program as an exe-based executable code. Additionally, the manual for understanding the Cryptft+ SW is included in the internal program so that it can be downloaded directly.

• Journal of Ocean Engineering and Technology
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• v.24 no.6
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• pp.76-80
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• 2010

Oil hydraulic piston pumps are being extensively used around the world, because of their simple design, light weight, effective cost, etc. An oil hydraulic pump is likely to have the serious problems of high leakage, friction, and low energy efficiency after a long period of use. In an oil hydraulic piston pump, the clearance between the valve block and piston plays an important role for volumetric and overall efficiency. In this study, the wear property of the SACM645 material with DLC coating used for a hydraulic piston pump was determined by experimentation with variable heat treatment. To investigate the effect according to the piston surface condition, five different types of specimens were prepared. The maximum tensile strengths of the QT and QT Nitration specimens had similar values of about 800 MPa, but the strains indicated a big difference. In a wear test, the wear characteristic of the DLC coating specimen was shown to be excellent. The QT, QT + IH, QT + Nitration, and matirx specimen showed similar wear characteristics. In the case of a dry condition without oil, the DLC coating specimen had good wear resistance, with no wear shown.