• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.792-793
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• 2016

Recent studies on a fusion of health care system and the information and communication technology of wearable is being developed Anytime and anywhere without being constrained to measure the biological information of the user. However existing wearable monitors the measured biological information. If the user is hard to deal with for the event of dangerous situations. In this paper, it proposes a system that identifies the status of a user to correct the problem it utilizes sensors and algorithms to measure the biological information. This enables the user will be able to respond quickly to dangerous situations. In the event of a dangerous situation, such as falling or stumbling sends an emergency alert to a designated guardian.

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.259-270
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• 2022

Artificial intelligence (AI) has been studied in various fields of medical imaging. Currently, top-notch deep learning (DL) techniques have led to high diagnostic accuracy and fast computation. However, they are rarely used in real clinical practices because of a lack of reliability concerning their results. Most DL models can achieve high performance by extracting features from large volumes of data. However, increasing model complexity and nonlinearity turn such models into black boxes that are seldom accessible, interpretable, and transparent. As a result, scientific interest in the field of explainable artificial intelligence (XAI) is gradually emerging. This study aims to review diverse XAI approaches currently exploited in medical imaging. We identify the concepts of the methods, introduce studies applying them to imaging modalities such as computational tomography (CT), magnetic resonance imaging (MRI), and endoscopy, and lastly discuss limitations and challenges faced by XAI for future studies.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.787-788
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• 2009

시계열 데이터(time-series data)는 연속적인 데이터를 고정된 시간 간격으로 샘플링한 실수 값들의 연속을 의미한다. 시계열 데이터의 예로는, 음악 및 동영상 데이터, 심전도 데이터, 주식 그래프 등의 데이터가 있다. 시계열 데이터는 다시 데이터베이스에 저장 되어있는 데이터 시퀀스(data sequence)와, 사용자에 의해 주어지는 질의 시퀀스(query sequence)로 분류된다. 시계열 데이터베이스(time-series database)에서 순위를 지원하는 서브시퀀스 매칭 방법(ranked subsequence matching)은 데이터 시퀀스와 질의 시퀀스가 주어졌을 때, 질의 시퀀스의 길이와 같은 데이터 시퀀스의 서브시퀀스(subsequence)들 중에서 질의 시퀀스와 가장 유사한 상위 k개의 서브시퀀스들을 찾는 것이다. 본 논문의 목적은 사용자가 매칭 방법에 대한 인식과 이해가 부족하더라도 기존의 콘솔 기반의 매칭 프로그램을 보다 쉽게 사용할 수 있도록 이용성을 향상시키기 위하여 시각화 툴을 개발하는 것이다. 구체적으로, 5가지 시각화(visualization) 기능을 제공하는 사용자 인터페이스를 구현하였다. 구현된 사용자 인터페이스를 통해 사용자가 기존의 매칭 프로그램을 보다 쉽고 간편하게 사용할 수 있도록 기여한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.372-378
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• 2020

Drones, which show strong growth in the fourth industry, are commonly used for disaster response. In the event of an actual disaster, local governments should carry out 13 cooperative functions to respond to the disaster, but there are difficulties in collecting on-site information in places where it is difficult for people to access or grasp the situation. Based on the 13 collaborative functions that are essential for operations in the event of a disaster, a utilization plan of highly utilized drones was derived. Through the analysis of overseas cases and drone utilization by each department, a total of 10 out of 13 collaborative functions of the Disaster and Safety Countermeasures Headquarters (disaster situation management, emergency life safety support, emergency recovery, disaster resource support, traffic measures, medical and quarantine services, disaster site environment maintenance, social order maintenance, search, rescue, and emergency) were derived. These results can enhance the efficiency of the disaster response by presenting a plan to utilize drone images for each function.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.1
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• pp.36-44
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• 2022

Reversible data hiding techniques have been developed to hide confidential data in the image by shifting the histogram of the image. These techniques have a weakness in which the security of hidden confidential data is weak. In this paper, to solve this drawback, we propose a technique of triple encrypting confidential data using pixel value information and hiding it in the cover image. When confidential data is triple encrypted using the proposed technique and hidden in the cover image to generate a stego-image, since encryption based on pixel information is performed three times, the security of confidential data hidden by triple encryption is greatly improved. In the experiment to measure the performance of the proposed technique, even if the triple-encrypted confidential data was extracted from the stego-image, the original confidential data could not be extracted without the encryption keys. And since the image quality of the stego-image is 48.39dB or higher, it was not possible to recognize whether confidential data was hidden in the stego-image, and more than 30,487 bits of confidential data were hidden in the stego-image. The proposed technique can extract the original confidential data from the triple-encrypted confidential data hidden in the stego-image without loss, and can restore the original cover image from the stego-image without distortion. Therefore, the proposed technique can be effectively used in applications such as military, medical, digital library, where security is important and it is necessary to completely restore the original cover image.

• Journal of radiological science and technology
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• v.30 no.2
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• pp.167-175
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• 2007

There are some positive effects by the introduction of PACS(Picture Archiving Communication System). This study is to analyze the mutual relation between before and after of the introduction of PACS in terms of the environment effect. It is supposed to cause the reduction of developing and fixing wastewater according to the increase in the rate of a non-film. This study will also show the amount of wastewater. Target places were the department of image medicine(diagnostic radiation) of the general hospitals in Seoul and Gyeonggi-Do, which are equiped with full PACS. The authors examined questionnaires on the number of projection, the number of indirect projection, the amount of the film used, the number of radiation image CD loan, the amount of the developing and fixing solution used, the change of the amount of fixing wastewater. According to the analysis, we analyzed the change of the amount of developing and fixing solution per a film and the change of the amount of developing and fixing wastewater which is supposed to be reduced proportionally by the introduction of PACS. We got conclusion as below after analyzing 8 hospitals except the largest and the least amount of examination, film used, developing and fixing solution and the amount of developing and fixing wastewater in order to decrease the deviation from 10 general hospitals located in Seoul and Gyeonggi-Do. We compared data one year before adopting PACS Versus 3 years after adopting PACS. 1. The frequences of examination increased to 7,357.7 cases per month but the amount of film used decreased to 90%, from 42,774.4 to 4,181.88 after adopting the PACS. 2. 3 years after adopting PACS, monthly average amount of developing solution used decreased to 92% and the monthly average amount of fixing solution decreased to 86%. 3. Monthly average amount of developing solution used per film increased to 1.49 times and fixing solution increased as much as three times. 4. Monthly average wastewater for developing decreased to 88% and wastewater for fixing decreased up to 87%. 5. Monthly average wastewater for developing per film increased to 3.77 times and wastewater for fixing increased to 3.85 times. Although the amount of film used and the amount of developing and fixing wastewater affected by the reduction of the developing and fixing solution became less on the whole by introduction of PACS, they did not decrease proportionally. Moreover the amount of the developing and fixing solution used and the amount of developing and fixing wastewater per a film increased. That means the expectation for an environmental improvement differs from the actual condition.

• Journal of radiological science and technology
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• v.36 no.4
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• pp.291-297
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• 2013

This study is aimed to evaluate the effect of $T_{1/2}$ upon count rates in the analysis of dynamic scan using NaI (Tl) scintillation camera, and suggest a new quality control method with this effects. We producted a point source with $^{99m}TcO_4^-$ of 18.5 to 185 MBq in the 2 mL syringes, and acquired 30 frames of dynamic images with 10 to 60 seconds each using Infinia gamma camera (GE, USA). In the second experiment, 90 frames of dynamic images were acquired from 74 MBq point source by 5 gamma cameras (Infinia 2, Forte 2, Argus 1). There were not significant differences in average count rates of the sources with 18.5 to 92.5 MBq in the analysis of 10 to 60 seconds/frame with 10 seconds interval in the first experiment (p>0.05). But there were significantly low average count rates with the sources over 111 MBq activity at 60 seconds/frame (p<0.01). According to the second analysis results of linear regression by count rates of 5 gamma cameras those were acquired during 90 minutes, counting efficiency of fourth gamma camera was most low as 0.0064%, and gradient and coefficient of variation was high as 0.0042 and 0.229 each. We could not find abnormal fluctuation in $x^2$ test with count rates (p>0.02), and we could find the homogeneity of variance in Levene's F-test among the gamma cameras (p>0.05). At the correlation analysis, there was only correlation between counting efficiency and gradient as significant negative correlation (r=-0.90, p<0.05). Lastly, according to the results of calculation of $T_{1/2}$ error from change of gradient with -0.25% to +0.25%, if $T_{1/2}$ is relatively long, or gradient is high, the error increase relationally. When estimate the value of 4th camera which has highest gradient from the above mentioned result, we could not see $T_{1/2}$ error within 60 minutes at that value. In conclusion, it is necessary for the scintillation gamma camera in medical field to manage hard for the quality of radiation measurement. Especially, we found a tendency that count rate changes over time at this study, and we proved that it can effect $T_{1/2}$. And also, there is need of appropriate phantoms and the method of quality management like this study, because there are not any advice or limitation degrees for domestic medical purpose scintillation camera.

• Journal of radiological science and technology
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• v.34 no.4
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• pp.263-269
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• 2011

Since the spine radiography were explained differently at every several hospitals and textbooks. the technique has not been accurately defined and interfered each other. We would like to define the most appropriate positioning for clinical cases, and reference books, by comparing scoliotic angle and lordotic angle. From Mar 2009 to Sep 2011, 85 patient cases were studied, who had not been undergone surgical treatment among spondylopathy patients. Scoliotic angle and lordotic angle were measured, using Cobb's method. We analyzed statistically using t-test(SPSS 18), and evaluated spine general radiography position. Moreover, we researched on the actual condition at 10 university hospitals in Seoul. The results of scoliotic angle measurement, the value at erect position showed 20.98% higher than supine position, and it has statistical significance (p<.01). In lordotic angle measurement, the value at neutral holding position represented 29.3% higher than supine position, and it also has statistical significance(p<.01). The results of clinical survey, supine posine(70.0%) took much higher possession than erect position(30.0%). In conclusion, compare to supine position, erect position shows increased scoliotic and lordotic angle. It was agreed with the importance of clinical erect position radiography, which gravity affects. So clinical radiologist must recognize the difference, and conduct an accurate study.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.81-87
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• 2016

With the rapid growth of the up-to-date smartphone and wireless network technologies, huge and various types of smart applications using these technologies are actively developed recently. Especially, multiplex types of smart applications using smartphone are developed and diffused with the rapid development of the ubiquitous sensor network technology using various sensors and the mobile computing technology that enables us to get network services at any time in any places. In this paper, we design a smart application that can accurately diagnose and process the current state of the local environment, objects, and persons remotely based on the context information such as local ecology, circumstances, medical or healthcare records and realtime sound or motion pictures using up-to-date samrtphone technology on the USN based mobile computing environment.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.15-28
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• 2019

Purpose Nuclear medicine was initially introduced in Korea in 1969 and widely applied to treat hyperthyroidism with $^{131}I$. Also, gamma camera was adopted in 1969 in the first place and its application has been growing continually in many ways. We analyzed long-term trend in nuclear medicine examinations for the last 2 decades. The purpose of this paper is to make predictions and to set both plans and directions on the development of nuclear medicine. Materials and Methods We analyzed the performance of nuclear medicine examinations and therapies performed in Asan Medical Center from 1998 to 2017. Results Results from the last 20 years regarding Bone scan, Renal scan, MUGA scan and $^{18}F$-FPCIT, Bone Mineral Density were on a increase. And Myocardium perfusion SPECT, Thyroid scan, Lung scan were on a decrease while $^{18}F-FDG$ PET maintained on a steady course. Until 2010 there was a positive performance with the therapy but after the excessive medical care in thyroid examination performance is at status quo. Key events such as a medical strike(2000), Middle-East Respiratory Syndrome (2015) influenced the overall performance of the therapy. Conclusion In order to promote a long-term growth in nuclear medicine examination and therapy, it is inevitable to respond to the changes in current medical environment. Furthermore, it is strongly suggested to put efforts to maintain and develop new examinations and clinical indicators.