• 한국재료학회지
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• 제29권5호
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• pp.336-341
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• 2019

The gas adsorption isotherm requires accurate measurement for the analysis of porous materials and is used as an index of surface area, pore distribution, and adsorption amount of gas. Basically, adsorption isotherms of porous materials are measured conventionally at 77K and 87K using liquid nitrogen and liquid argon. The cold volume calibration in this conventional method is done simply by splitting a sample cell into two zones (cold and warm volumes) by controlling the level sensor in a Dewar filled with liquid nitrogen or argon. As a result, BET measurement for textural properties is mainly limited to liquefied gases (i.e. $N_2$ or Ar) at atmospheric pressure. In order to independently investigate other gases (e.g. hydrogen isotopes) at cryogenic temperature, a novel temperature control system in the sample cell is required, and consequently cold volume calibration at various temperatures becomes more important. In this study, a cryocooler system is installed in a commercially available BET device to control the sample cell temperature, and the automated cold volume calibration method of temperature variation is introduced. This developed calibration method presents a reliable and reproducible method of cryogenic measurement for hydrogen isotope separation in porous materials, and also provides large flexibility for evaluating various other gases at various temperature.

• 천문학회보
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• 제43권2호
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• pp.48.4-49
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• 2018

We studyed an Korean astrolabe made by Ryu Geum (1741~1788), the late Joseon Confucian scholar. It has a diameter of 17 cm and a thickness of 6 mm and is now owned by Museum of Silhak. In the 1267 of the reign of Kublai Khan of Mogol Empire, Jamal al Din, an Ilkhanate astronomer, present an astrolabe to his emperor together with 6 astronomical instruments. In 1525, an astrolabe was first made in Korea by Lee, Sun (李純, ?~?), a Korean astronomer and royal official of Joseon Dynasty. He was referred to Gexiang xinshu, a Mongloian-Chinese book by Zhao, Youqin (1280-1345), an astronomer of Mongolian Empire. This astrolabe has not been left. In the mid-17th century, an astrolabe was introduced to Joseon again through Hungai tongxian tushuo (渾蓋 通憲圖設) edited by Chinese Mathematician Li Zhi-zao (李之藻, 1565~1630), that originated from Astrolabium (1593) of Christoph Clavius (1538-1612). It seems that Ryu refered to Hungai tongxian tushuo which affect to Hongae-tongheon-ui (渾蓋通憲儀) edited by Nam, Byeong-Cheol (南秉哲, 1817~1863). We analysis lots of circles on the mother and a set of index from the rete of of Ryu's astrolabe. We find that the accuracy of circles has about 0.2~0.4 mm in average if the latitude of this astrolabe is 38 degrees. 11 indices of the rete point bright stars of the northern and southern celestial hemisphere. Their tip's accuracies are about $2^{\circ}.9{\pm}3^{\circ}.2$ and $2^{\circ}.3{\pm}2^{\circ}.8$ on right ascension and declination of stars respectively.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.525-527
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• 2019

심정지(Cardiac arrest)는 원인과 관계없이 심장의 박동이 정지되어 발생하는 일련의 상태를 말한다. 심정지 발생 시 환자의 생명을 구하기 위한 유일한방법 중 하나는 심폐소생술이며 이 술기를 통하여 순환을 유지 시킬 수 있고, 고품질의 심폐소생술은 환자의 생존률과 신경학적 예후에 영향을 미치기 때문에 매우 중요한 술기이다. 영아 심폐소생술의 경우 두 손가락으로 가슴을 압박하는 방법을 사용한다. 하지만 이 방법은 해부학적으로 손가락의 피로도가 가중되고 수직압박이 힘들어 미국심장협회에서 권장한 가슴압박깊이에 도달하기 힘들 수 있다. 이 연구는 영아 심폐소생술 중 가슴압박 시행 시 새로운 가슴압박법의 효과를 검증하고, 고품질의 심폐소생술을 위한 기초자료를 제공하고자 한다. 연구결과 가슴압박 방법에 따라 가슴의 평균압박깊이 및 평균압박 속도가 유의한 차이가 있었다(p<0.001) 또한 가슴압박의 편리성 및 통증정도에서 유의한 차이를 보였다. 본 연구의 결과를 종합해 볼 때 영아 심폐소생술 중 새로운 가슴압박법 시행 시 정확도가 높아지고, 가슴압박 깊이가 나아져 가슴압박의 질적 지표가 개선되었음을 알 수 있었다.

• International Journal of Computer Science & Network Security
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• 제21권8호
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• pp.267-275
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• 2021

Smart application is developed in this paper by using an android-based platform to automatically determine the human emergency state (Lifesaver) by using different technology sensors of the mobile. In practice, this Lifesaver has many applications, and it can be easily combined with other applications as well to determine the emergency of humans. For example, if an old human falls due to some medical reasons, then this application is automatically determining the human state and then calls a person from this emergency contact list. Moreover, if the car accidentally crashes due to an accident, then the Lifesaver application is also helping to call a person who is on the emergency contact list to save human life. Therefore, the main objective of this project is to develop an application that can save human life. As a result, the proposed Lifesaver application is utilized to assist the person to get immediate attention in case of absence of help in four different situations. To develop the Lifesaver system, the GPS is also integrated to get the exact location of a human in case of emergency. Moreover, the emergency list of friends and authorities is also maintained to develop this application. To test and evaluate the Lifesaver system, the 50 different human data are collected with different age groups in the range of (40-70) and the performance of the Lifesaver application is also evaluated and compared with other state-of-the-art applications. On average, the Lifesaver system is achieved 95.5% detection accuracy and the value of 91.5 based on emergency index metric, which is outperformed compared to other applications in this domain.

• 한국차세대컴퓨팅학회논문지
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• 제14권6호
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• pp.7-14
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• 2018

다중 뷰 비디오로부터 두드러진 정보 추출은 인터뷰, 인트라 뷰간 상관관계와 계산 비용 때문에 매우 어려운 영역입니다. 매우 높은 계산 복잡성을 지닌 멀티 뷰 비디오에서 키프레임을 추출하기 위해 개발된 몇 가지 기술이 있습니다. 이 논문에서, 우리는 내부에 존재하는 엔트로피와 복잡한 정보를 사용하여 멀티 뷰 비디오의 키프레임 추출 접근 방식을 제시합니다. 첫 번째 단계에서는 프레임 사이의 SSIM값을 기반으로 각 보기에서 전체 비디오의 대표 샷을 추출합니다. 두 번째 단계에서는 서로 다른 보기의 모든 샷 프레임에 대한 엔트로피와 복잡성 점수가 계산됩니다. 마지막으로 엔트로피와 복잡성 점수가 가장 높은 프레임은 키 프레임으로 간주됩니다. 제안된 시스템은 사용 가능한 Office벤치마크 데이터 세에서 주관적으로 평가되며, 정확성과 시간 복잡성의 측면에서 결과는 편리합니다.

• 정보보호학회논문지
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• 제14권2호
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• pp.23-33
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• 2004

인터넷 환경의 급속한 발전으로 인하여 이메일을 통한 메시지 교환은 급속히 증가하고 있다. 그러나 이메일의 편리성에도 불구하고 개인이나 기업에서는 스팸메일로 인한 시간과 비용의 낭비가 크게 증가하고 있다. 이러한 스팸메일에 대한 문제들을 해결하기 위하여 많은 방법들이 연구되고 있으며, 대표적인 방법으로 키워드를 이용한 패턴매칭이나 나이의 베이지안 방식과 같은 확률을 이용한 방법들이 있다. 본 논문에서는 기존의 연구에 대한 문제점을 보완하기 위하여 패턴 분류문제에 있어서 우수한 성능을 보이는 Support Vector Machine을 사용하여 정상적인 메일과 스팸메일을 분류하는 방안을 제시하였으며, 특히 n-Gram을 사용하여 생성된 색인어와 단어사전을 학습데이터 생성에 사용함으로서 효율적인 학습을 수행하도록 하였다. 결론에서는 제안된 방법에 대한 성능을 검증하기 위하여 기존의 연구 결과와 비교함으로서 제안된 방법의 성능을 검증하였다.

• 대한의용생체공학회:의공학회지
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• 제42권3호
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• pp.80-85
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• 2021

We developed a model to classify the absence of cervical cancer using deep learning from the cervical image to which the histogram equalization algorithm was applied, and to compare the performance of each model. A total of 4259 images were used for this study, of which 1852 images were normal and 2407 were abnormal. And this paper applied Image Sharpening(IS), Histogram Equalization(HE), and Contrast Limited Adaptive Histogram Equalization(CLAHE) to the original image. Peak Signal-to-Noise Ratio(PSNR) and Structural Similarity index for Measuring image quality(SSIM) were used to assess the quality of images objectively. As a result of assessment, IS showed 81.75dB of PSNR and 0.96 of SSIM, showing the best image quality. CLAHE and HE showed the PSNR of 62.67dB and 62.60dB respectively, while SSIM of CLAHE was shown as 0.86, which is closer to 1 than HE of 0.75. Using ResNet-50 model with transfer learning, digital image-processed images are classified into normal and abnormal each. In conclusion, the classification accuracy of each model is as follows. 90.77% for IS, which shows the highest, 90.26% for CLAHE and 87.60% for HE. As this study shows, applying proper digital image processing which is for cervical images to Computer Aided Diagnosis(CAD) can help both screening and diagnosing.

• Journal of Animal Science and Technology
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• 제62권6호
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• pp.884-892
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• 2020

Corticosterone is known as a biological stress index in many species including birds. Feather corticosterone concentration (FCC) has increasingly been used as a measure for chronic stress status in broiler chickens. As sample preparation is the first step of analytical process, different techniques of feather matrix disruption need to be validated for obtaining better result in analysing corticosterone extraction. The current study was a validation of pulverizing the feather by bead beater (BB) and surgical scissors (SS) processing prior to corticosterone extraction in feather of broiler chickens. The type of feather processing prior to the hormone extraction may alter the final output. Thereby, finding a standard method according to laboratory facilities is pivotal. This study carried out to determine the effects of feather pulverization methods on the extraction amount of corticosterone in broiler chickens. Feathers were sampled from four weeks old Ross 308 broiler chickens (n = 12 birds). All broiler chickens were kept under the same environmental condition and had access to feed and water. Feather samples were assigned to one of the following processing methods 1) using a BB for pulverizing and 2) using a SS for chopping into tiny pieces. Each sample was duplicated into two wells during enzyme immunoassay (EIA) analysis to improve the accuracy of the obtained data. The results showed lower standard errors and constant output of FCC by using the BB method compared with the SS method. Overall comparison of FCC showed a significantly higher (p < 0.001) amount of the FCC in the BB compared with the SS. Overall, using the BB method is recommended over the SS method for feather processing due to the ability to homogenize a large number of samples simultaneously, ease of use and greater extraction of feather corticosterone.

• Journal of Radiation Protection and Research
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• 제45권4호
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• pp.171-177
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• 2020

Background: This study aims to determine the effective atomic number (Zeff) from dual-energy image sets obtained using a conventional computed tomography (CT) simulator. The estimated Zeff can be used for deriving the stopping power and material decomposition of CT images, thereby improving dose calculations in radiation therapy. Materials and Methods: An electron-density phantom was scanned using Philips Brilliance CT Big Bore at 80 and 140 kVp. The estimated Zeff values were compared with those obtained using the calibration phantom by applying the Rutherford, Schneider, and Joshi methods. The fitting parameters were optimized using the nonlinear least squares regression algorithm. The fitting curve and mass attenuation data were obtained from the National Institute of Standards and Technology. The fitting parameters obtained from stopping power and material decomposition of CT images, were validated by estimating the residual errors between the reference and calculated Zeff values. Next, the calculation accuracy of Zeff was evaluated by comparing the calculated values with the reference Zeff values of insert plugs. The exposure levels of patients under additional CT scanning at 80, 120, and 140 kVp were evaluated by measuring the weighted CT dose index (CTDIw). Results and Discussion: The residual errors of the fitting parameters were lower than 2%. The best and worst Zeff values were obtained using the Schneider and Joshi methods, respectively. The maximum differences between the reference and calculated values were 11.3% (for lung during inhalation), 4.7% (for adipose tissue), and 9.8% (for lung during inhalation) when applying the Rutherford, Schneider, and Joshi methods, respectively. Under dual-energy scanning (80 and 140 kVp), the patient exposure level was approximately twice that in general single-energy scanning (120 kVp). Conclusion: Zeff was calculated from two image sets scanned by conventional single-energy CT simulator. The results obtained using three different methods were compared. The Zeff calculation based on single-energy exhibited appropriate feasibility.

• Steel and Composite Structures
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• 제39권1호
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• pp.51-64
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• 2021

This paper presents a high-order shear and normal deformation theory for the bending of FGM plates. The number of unknowns and governing equations of the present theory is reduced, and hence makes it simple to use. Unlike any other theory, the number of unknown functions involved in displacement field is only four, as against five or more in the case of other shear and normal deformation theories. Based on the novel shear and normal deformation theory, the position of neutral surface is determined and the governing equilibrium equations based on neutral surface are derived. There is no stretching-bending coupling effect in the neutral surface-based formulation, and consequently, the governing equations of functionally graded plates based on neutral surface have the simple forms as those of isotropic plates. Navier-type analytical solution is obtained for functionally graded plate subjected to transverse load for simply supported boundary conditions. The accuracy of the present theory is verified by comparing the obtained results with other quasi-3D higher-order theories reported in the literature. Other numerical examples are also presented to show the influences of the volume fraction distribution, geometrical parameters and power law index on the bending responses of the FGM plates are studied.