• Journal of Practical Engineering Education
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• 제15권3호
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• pp.641-647
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• 2023

In the fintech environment, ensuring secure financial transactions with smartphones requires authenticating the device owner. Smartphone authentication techniques encompass a variety of approaches, such as passwords, biometrics, SMS authentication, and more. Among these, password-based authentication is commonly used and highly convenient for user authentication. Although it is a simple authentication mechanism, it is susceptible to eavesdropping and keylogging attacks, alongside other threats. Security keypads have been proposed to address vulnerabilities in password input on smartphones. One such innovation is a group keypad, resistant to attacks that guess characters based on touch location. However, improvements are needed for user convenience. In this study, we aim to propose a method that enhances convenience while being resistant to eavesdropping and recording attacks on the existing group keypad. The proposed method uses new signs to allow users to verify instead of the last character confirmation easily and employs dragging-to-touch for blocking recording attacks. We suggest diverse positioning methods tailored for domestic users, improving efficiency and security in password input compared to existing methods.

• Journal of Advanced Navigation Technology
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• 제25권6호
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• pp.441-449
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• 2021

With advances in autonomous vehicles, there is a growing demand for more accurate position estimation. Especially, this is a case for a moving robot for the indoor operation which necessitates the higher accuracy in position estimation when the robot is required to execute the task at a predestined location. Thus, a method for improving the position estimation which is applicable to both the fixed and the moving object is proposed. The proposed method exploits the initial position estimation from Bluetooth beacon signals as observation signals. Then, it estimates the gravitational acceleration applied to each axis in an inertial frame coordinate through computing roll and pitch angles and combining them with magnetometer measurements to compute yaw angle. Finally, it refines the control inputs for an object with motion dynamics by computing acceleration on each axis, which is used for improving the performance of Kalman filter. The experimental assessment of the proposed algorithm shows that it improves the position estimation accuracy in comparison to a conventional Kalman filter in terms of average error distance at both the fixed and moving states.

• Journal of the Korea Institute of Building Construction
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• 제23권5호
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• pp.629-638
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• 2023

This study introduces an innovative approach to monitor the whereabouts of workers within indoor construction settings. While traditional modalities such as GPS and NTRIP have demonstrated efficacy for outdoor localizations, their precision dwindles in indoor environments. In response, this research advocates for the adoption of Aruco markers. Leveraging computer vision technology, these markers facilitate the quantification of the distance between a worker and the marker, subsequently pinpointing the worker's instantaneous location with heightened accuracy. The methodology's efficacy was rigorously evaluated in a real-world construction scenario. Parameters including system stability, the influence of lighting conditions, the extremity of measurable distances, and the breadth of recognition angles were methodically appraised. System stability was ascertained by maneuvering the camera at a uniform velocity, gauging its marker recognition prowess. The impact of varying luminosity on marker discernibility was scrutinized by modulating the ambient lighting. Furthermore, the camera's spatial movement ascertained both the upper threshold of distance until marker recognition waned and the maximal angle at which markers remained discernible.

• Journal of the Korean Society of Radiology
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• 제83권3호
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• pp.724-729
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• 2022

A duodenal web is an incomplete diaphragm of the duodenal lumen that causes a partial or (intermittent) complete obstruction. The size of a duodenal web's aperture determines the degree of obstruction, age at presentation, and radiologic findings. We report a case of duodenal web incidentally diagnosed in a 14-month-old boy who presented to the hospital after ingesting a foreign body. We provide a comprehensive report of multiple studies through abdominal radiograph, upper gastrointestinal study, endoscopy, and surgical findings. We emphasize that the duodenum should be considered as the location of the obstruction when infants exhibit delayed discharge or dynamic positioning of a foreign body in a radiologic examination.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• 제39권4호
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• pp.251-261
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• 2003

To measure the GPS position accuracy and its distribution according to the length of the baseline, 30 minutes to 24 hours observations at the fixed location were conducted with two GPS receivers (Ll, 12 channels) on May 29 to June 2, 2002. The GPS data received at the reference station, the rover station and the ordinary times GPS observation station operated by the National Geography Institute in Korea were processed in kinematic and static post-processing methods with a post -processing software. The results obtained are summarized as follows: 1. The number of the satellite that could be observed continuously more than six hours was 16 and most of these satellites were positioned at east-west direction on May 31, 2002. The number of the satellite observed and the geometric dilution of precision (GDOP) determined by the average of every 10 minute for the day were 8 and 3.89, respectively. 2. Both the average GPS positions before and after post-processing were shifted (standalone: 1.17 m, post -processing: 0.43m) to the south and west. The twice distance root mean square (2drms) measured with standalone was 6.65m. The 2drms could be reduced to 33.8% (standard deviation 0=17.2) and 5.3% (0=2.2) of standalone by the kinematic and the static post-processing methods, respectively. 3. The relationship between the length of the baseline x (km) and the 2drms y (m) obtained by the static post-processing method was y=0.00l6x+0.006 $(R^2=0.87)$. In the case of the positioning with the static post-processing method using the GPS receiver, it was found that a positioning within 20cm 2drms was possible when the length of the baseline was less than 100km and the receiving time of the GPS is more than 30 minutes.

• Journal of the Korean Institute of Landscape Architecture
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• 제36권4호
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• pp.83-99
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• 2008

Images of Seong-Nam appears different according to diverse conditions. This study was intended to analyze the differences of cognition by personal characteristics such as age, gender, location, and period when an individual evaluates an urban image. This research focused on the interpretation of the visualized results from Multidimensional Scaling (MDS) and Individual Difference Scaling (INDSCAL) with two questionnaires. This study can be summarized as follows: 1. Namhan Sansung was ranked as the first symbolic property by citizens in Seong-Nam. Next was Yuldong Park, followed by Bundang Central Park, Seohyun Station including Samsung Plaza, and, finally, Moran Market. This trend also similarly appeared in the selection of preferred places. 2. There were no statistical differences in trends of choice of symbolic landmarks and preferred places according to age, gender, and period; however, there were meaningful differences according to location. 3. The total image of Seong-Nam was positioned to be separated from images of other districts and landmarks on the image spatial plot by MDS; however, images of the old and new district were plotted close to symbolic landmarks where located around each district. 4. INDSCAL illustrated that men weighted the historical meaning while women weighted preference and city size when evaluating an urban image. On the other hand, there was no difference in cognitive trends according to age, location, and period. Until now, an individual difference in the cognition and evaluation of an urban image was a socially accepted notion. However, this study verified the difference according to personal characteristics and developed a practical tool to analyze an individual cognition trend about a city image.

• Korean Security Journal
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• 제13호
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• pp.145-168
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• 2007

Like to change to the information-oriented society, the guard service needs to be changed. The communication and hardware technology develop rapidly and according to the internet environment change from cable to wireless, modern person can approach every kinds of information service using wireless communication machinery which can be moved such as laptop, computer, PDA, mobile phone and so on, LBS field which presents the needing information and service at anytime, anywhere, and which kinds of device expands it's territory all the more together with the appearance of ubiquitous concept. LBS use the chip in the mobile phone and make to confirm the position of the joining member anytime within several tens centimeters to hundreds meters. LBS can be divided by the service method which use mobile communication base station and apply satellite. Also each service type can be divided by location chase service, public safe service, location based information service and so on, and it is the part which will plan with guard service development. It will be prospected 8.460 hundred million in 2005 years and 16.561 hundred million in 2007 years scale of market. Like this situation, it can be guessed that the guard service has to change rapidly according to the LBS application. Study method chooses documentary review basically, and at first theory method mainly uses the second documentary examination which depends on learned journal and independent volume which published in the inside and the outside of the country, internet searching, other kinds of all study report, statute book, thesis which published at public order research institute of the Regional Police Headquarter, police operation data, data which related with statute, documents and statistical data which depend on private guard company and so on. So the purpose of the study gropes in accordance with the LBS application, and present the problems and improvement method to analyze indirect of manager side of operate guard adaptation service of LBS, government side which has to activate LBS, systematical, operation management, manpower management and education training which related with guard course side which has to study and educate in accordance with application of the new guard service, as well as intents to excellent quality service of guard.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제18권11호
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• pp.374-380
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• 2017

In this study, we analyzed the situation of the 119 emergency medical service zone of H town, countryside of Y city from January 1st, 2015 to December 31st, 2016 and then, on the basis of this analysis, we investigated the present condition of the patient-transportation service of the 119 emergency medical service to provide the basic data in order for patients to use the emergency medical service more efficiently. We analyzed the data with SPSS 21.0 using frequency analysis and, after positioning the virtual 119 emergency medical service, we analyzed the data of the transportation time and transportation distance by using GIS. The results of this study show that the use of the 119 emergency medical service for people over 65 years old represents approximately 57% of the total number of patients transported, The average distance and time of the real moving reaction are 6.41 km and 11.86 min, respectively. The distance and time from the pick-up location to the hospital are 18.24 km and 21.52 min, respectively. Given the present position of the 119 emergency medical service, the results of this analysis using GPS show that the (average) distance and time from the 119 emergency medical service to Jang * Ri town are 9.12 km and 12 min, and the (average) total distance and time to arrive at the hospital after the emergency medical service picks up the patient are 36.83 km and 62 min, respectively. In the case of the virtual emergency medical service, the total distance and time required to arrive at the hospital after the emergency medical service picks up the patient are 27.71km and 50min, respectively. The results of this study showed that the present position of the 119 emergency service does not provide the optimum distance and time from the patient's location to the hospital. Therefore, we consider that the repositioning of the 119 emergency medical center is necessary, in order to reduce the time required for the emergency medical service to move to the patient's location and then bring the patient to the hospital.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.278-280
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• 2012

We are propose the position of the node context-awareness information and the validity of the head node in the path according to the clustering how to elect one of the energy efficiency ECOPS (Energy Conserving Optimal path Schedule) algorithm. Existing LEACH algorithm to elect the head node when the node's energy probability distribution function based on the management of the head node is optional cycle. However, in this case, the distance of the relay node status information including context-awareness parameters does not reflect. These factors are not suitable for the relay node or nodes are included in the probability distribution, if the head node selects occurs. In particular, to solve the problems from the LEACH-based hierarchical clustering algorithms, this study defines location with the status context information and the residual energy factor in choosing topology of the structure adjacent nodes. ECOPS algorithm that contextual information is contributed for head node selection in topology protocols. The proposed ECOPS algorithm has the head node replacement situations from the candidate head node in the optimal path and efficient energy conservation that is the path of the member nodes. The new head node election show as the entire node lifetime and network management technique improving the network lifetime and efficient management the simulation results.

• Journal of Aerospace System Engineering
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• 제14권5호
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• pp.122-129
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• 2020

Surion is required to install radios (U/VHF-AM, VHF-FM) capable of omni-directional communication. Therefore, this paper demonstrates the antenna performance test for the installation of the Surion communication antenna and the selection of optimal location. A simulation pattern analysis was performed employing the antenna, and a coupling test was performed by creating a new evaluation criterion. In addition, the results of the pattern flight test conducted at the previously suggested 1:20 turn and separation distance ratio were observed to be normal. However, the occurrence of voice cutoff was noted in the long-distance flight test. Therefore, in this paper, 1:300 (15 NM) is proposed as a new optimal ratio for predicting the long-distance flight test results in advance. Finally, the effectiveness of the proposed evaluation criteria was verified through long-distance flight tests. Consequently, it is expected to reduce the development schedule and cost by reducing the trial and error of the performance test for the Surion model. Also, the results of this study are expected to be used as standards for the installation of communication antenna and quality tests for other helicopters.