• Imaging Science in Dentistry
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• v.54 no.3
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• pp.289-295
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• 2024

Purpose: This study examined the influence of metal artifact reduction (MAR), the application of sharpening filters, and their combination on the diagnosis of horizontal root fracture (HRF) in teeth adjacent to a zirconia implant on cone-beam computed tomography (CBCT) examinations. Materials and Methods: Nineteen single-rooted teeth (9 with HRF and 10 without) were individually positioned in the right central incisor socket of a dry human maxilla. A zirconia implant was placed adjacent to each tooth. Imaging was performed using an OP300 Maxio CBCT (Instrumentarium, Tuusula, Finland) unit with the following settings: a current of 8 mA, both MAR modes(enabled and disabled), a 5×5 cm field of view, a voxel size of 0.085 mm, and a peak kilovoltage of 90 kVp. Four oral and maxillofacial radiologists independently evaluated the CBCT scans under both MAR conditions and across 3 levels of sharpening filter application (none, Sharpen 1×, and Sharpen 2×). Diagnostic metrics were calculated and compared using 2-way analysis of variance (α=5%). The weighted kappa test was used to assess intra- and inter-examiner reliability in the diagnosis of HRF. Results: MAR tool activation, sharpening filter use, and their combination did not significantly impact the area under the receiver operating characteristic curve, sensitivity, or specificity of HRF diagnosis (P>0.05). Intra- and inter-examiner agreement ranged from fair to substantial. Conclusion: The diagnosis of HRF in a tooth adjacent to a zirconia implant is not affected by the activation of MAR, the application of a sharpening filter, or the combination of these tools.

• Journal of the Society of Disaster Information
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• v.20 no.3
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• pp.635-643
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• 2024

Purpose: This study is to seek the introduction of big data and AI technologies to strengthen the safety of local festivals, and to present legal application measures to effectively realize them. Method: diagnose the current status of the legal system related to the safety of local festivals through literature review, case analysis, and examination of legal systems, and to propose safety management measures based on big data and AI, as well as related legal improvement measures that can effectively support these initiatives. Result: Local festival safety-related laws have different purposes and regulations, and it has been confirmed that there are many difficulties for organizers to comply and apply them in an integrated manner. In particular, a clear legal basis is required for the introduction of big data and AI technologies, and it is important to establish a consistent safety management operating system through an integrated legal system. Conclusion: In order to introduce big data and AI technologies to local festivals and enhance safety, the following legal improvements are necessary: first, the establishment of an integrated legal system; second, the mandatory allocation of safety management costs; and third, the establishment and operation of an integrated control center.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.12
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• pp.3218-3241
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• 2023

Financial fraud undermines the sustainable development of financial markets. Financial statements can be regarded as the key source of information to obtain the operating conditions of listed companies. Current research focuses more on mining financial digital data instead of looking into text data. However, text data can reveal emotional information, which is an important basis for detecting financial fraud. The audit opinion of the financial statement is especially the fair opinion of a certified public accountant on the quality of enterprise financial reports. Therefore, this research was carried out by using the data features of 4,153 listed companies' financial annual reports and audits of text opinions in the past six years, and the paper puts forward a financial fraud detection model integrating audit opinions. First, the financial data index database and audit opinion text database were built. Second, digitized audit opinions with deep learning Bert model was employed. Finally, both the extracted audit numerical characteristics and the financial numerical indicators were used as the training data of the LightGBM model. What is worth paying attention to is that the imbalanced distribution of sample labels is also one of the focuses of financial fraud research. To solve this problem, data enhancement and Focal Loss feature learning functions were used in data processing and model training respectively. The experimental results show that compared with the conventional financial fraud detection model, the performance of the proposed model is improved greatly, with Area Under the Curve (AUC) and Accuracy reaching 81.42% and 78.15%, respectively.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.629-636
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• 2024

In construction projects, the safety and productivity of machinery operations are of paramount importance. Contemporary research and industry endeavors predominantly concentrate on equipping machine operators with sensory information and establishing a comprehensive situation-aware operating environment, such as virtual reality-based machine manipulation training. However, significant limitations exist in direct information exchange and processing by on-site personnel. Notably, research on analyzing communication patterns in construction machinery operations remains scarce despite its critical role in preventing hazardous instructions/actions and enhancing machinery work efficiency. Thus, this research aims to (1) develop a novel interpreter modeling system predicated on millimeter-wave radar technology and (2) select the crane as an illustration to investigate the potential applications of this emerging communication paradigm during construction machinery operations. In this investigation, a spatial gesture signal interpreter was devised specifically for machine operators and signalers to augment the quality of communication during the execution of spatial localization tasks. Corresponding limitations that will be encountered in current communication systems were also addressed. This research uses a 60 GHz millimeter wave radar as a gesture trajectory detector, with the benefits of portability and robustness. Its millimeter-level precision enables the capture of highly accurate micro-gestures. The research constructs a novel 3D Spatial Gesture-based Trajectory Modeling system, which will be compared with traditional communication models in future research stages.

• Journal of The Korean Association of Information Education
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• v.11 no.1
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• pp.21-28
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• 2007

Along with the development of telecommunication technology, educational role has been considerably changed and NEIS is introduced and operated for the digital educational administration. However, the function of NEIS is so limited when operated in each school. As a result, Korean government prepares the plan to install and operate a new School Affairs System by separating 3 areas from 27 areas of NEIS. School Affairs System has been used in schools since March, 2006. In this regard, this study attempts to analyze the current status and tasks of using the system in elementary schools. The result of the study shows that about 67% teachers use the system once or twice a day. Most of teachers answer that they get help from other teachers if they have any problem in operating the system. Many teachers affirmatively answer to the design and function of the system, and they are satisfied with the convenience and efficiency of the system. However, they feel difficulty to be familiar with the system sue to the frequent change. The importance of electronic certificate and personal information is well recognized and managed in terms of the security of the system. Facilities need to be well equipped, and information exchange system need to be developed to accept each school's request to improve the function of the system. In addition, applicable laws need to be arranged, clear guideline of educational administration agency and principal's strong intention are required to relieve teachers' work load.

• Journal of the Korean Chemical Society
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• v.50 no.6
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• pp.454-463
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• 2006

refractory organic compounds in aqueous solution are not readily removed by the existing conventional wastewater treatment process. In recent years, the sonolysis and electrochemical oxidation process had been shown to be promising for wastewater treatment due to the effectiveness and easiness in operation. This study was performed to investigate the characteristics of sonolytic and electrolytic decomposition as the basic data for development of the wastewater treatment process. Trichloroethylene(TCE) and 2,4- dichlorophenol(2,4-DCP) were used as the samples, and their destruction efficiency were measured with various operating parameters, such as initial solution concentration, initial solution pH, reaction temperature, sonic power and current density. Also, the decomposition mechanism conformed indirectly with the effect of NaHCO3 as a radical scavenger on the decomposition reaction. Thermal decompositon reaction is predominant for TCE but thermal and radical decompositon reactions were dominant for 2,4-DCP. Results showed that the destruction efficiencies of all samples were above 65% within 120 minutes by sonolysis and electrolysis at the same time, and were increased with increasing initial concentration, sonic power and current density. Destruction efficiency of TCE was high in the acidic solution, but 2,4-DCP showed high destruction efficiency in basic solution.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.3
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• pp.125-133
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• 2002

In this paper, we present an efficient broadcast protocol, called Btoken, that ensures total ordering of messages and atomicity of delivery in the large scaled distributed systems. Unlike the existing token-passing based protocol, Btoken does not circulate a token around the ring, instead, it uses three kinds of control messages for token transmission. The token has a sequence number field for broadcasting message, and the only site having the token can broadcast a message. When a site wishes to broadcast, It must send a message to the token site requesting the token. The token site sends a message with the token to the requester When the requester receives the token, it becomes the current token site and broadcasts a new message after setting sequence number derived from a field of the token into its message. Upon reception of it, any operating member is informed the position of the token site and will send token requesting message to the new token site. However, the other site may request the token to the old token site prior to receiving the broadcast message from the new token site. To resolve this problem, Btoken uses a message which is sent to the current token site by the old token site notifying who is the next token requester. Results of our simulation of the protocol show that Btoken is more efficient in the large scaled distributed system compared to existing broadcast protocols.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.6
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• pp.650-657
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• 2001

This paper explains the process of designing a shielded encircling remote field eddy current (RFEC) probe to inspect nuclear fuel cladding tubes and investigates resulting signal characteristics. To force electromagnetic energy from exciter coil to penetrate into the tube, exciter coil is shielded outside by laminations of iron insulated electrically from each other. Effects of shielding and the proper operating frequency are studied by the finite element analysis and the location for sensor coil is decided. However, numerically simulated signals using the designed probe do not clearly show the defect indication when the sensor passes a defect and the other indication appeared as the exciter passes the defect is affected by the shape of shielding structure, which demonstrates that the sensor is directly affected by exciter fields. For this reason, the sensor is also shielded outside and this shielding dramatically improves signal characteristics. Numerical modeling with the finally designed probe shows very similar signal characteristics to those of inner diameter RFEC probe. That is, phase signals show almost equal sensitivity to inner diameter and outer diameter defects and the linear relationship between phase signal strength and defect depth is observed.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.17 no.1
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• pp.28-37
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• 2006

Purpose: Evaluation of vocal cord vibration is very important in cases of voice disorders. There are several equipments for examining the vocal fold vibration such as laryngeal stroboscope, ultra high-speed digital imaging system, and videokymograph. Among these, laryngeal stroboscope is the most popular equipment because of easy to examine the laryngeal pathology. However, current laryngo-stroboscopes are too bulky to move and relatively expensive. The purpose of this research is to develope a portable laryngeal stroboscope of equivalent performance with the current equipments. Methods and Materials: Recently developed high luminescent white LEDs(light emitting diodes) are placed at the head of the endoscope as light sources for the CCD image sensor which is also placed at the head with imaging lens. This arrangement eliminates the bulky light source like expensive halogen or xenon lamps as well as the optical light guiding cables. The LEDs are controlled to flash in phase with the voice frequency of the examinee. The CCD captures these strobo images and converts them into video signals for examinations. Results: There was no functional differences between preexisting stroboscope and the newly developed stroboscope of this study. LED light sources and microprocessor based control circuits of the stroboscope enabled the development of flicker-less, hand-held, portable and battery-operating stroboscope. Conclusion: The developed stroboscope is cost-effective, small-sized, easy to use and very easy desirable to bring and to use in any place.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.5
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• pp.485-492
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• 2009

The thermal fatigue crack(TFC) is one of the life-limiting mechanisms at the nuclear power plant operating conditions. In order to evaluate the structural integrity, various non-destructive test methods such as radiographic test, ultrasonic test and eddy current are used in the industrial field. However, these methods have restrictions that defect detection is possible after the crack growth. For this reason, acoustic emission testing(AET) is becoming one of powerful inspection methods, because AET has an advantage that possible to monitor the structure continuously. Generally, every mechanism that affects the integrity of the structure or equipment is a source of acoustic emission signal. Therefore the noise filtering is one of the major works to the almost AET researchers. In this study, acoustic emission signal was collected from the pipes which were in the successive thermal fatigue cycles. The data were filtered based on the results from previous experiments. Through the data analysis, the signal characteristics to distinguish the effective signal from the noises for the TFC were proven as the waveform difference. The experiment results provide preliminary information for the acoustic emission technique to the continuous monitoring of the structure failure detection.