• 한국산학기술학회논문지
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• 제20권10호
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• pp.1-6
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• 2019

IoT 기반의 스마트홈, 핀테크 등의 모바일 기술이 발달하면서 스마트 디바이스를 이용한 사용자 인증이 일상생활에서 널리 사용되고 있다. 이에 따라 기존의 비밀번호와 같은 지식 기반의 인증 방법에서 스마트 디바이스를 이용한 존재 기반의 생체인증이 새로운 주류가 되었고, 맥파, 지문, 얼굴, 홍채 등 다양한 생체인증 중에 신체적 특성상 위변조 가능성이 낮고 고유한 특징으로 개인 식별성이 높은 ECG(Electrocardiogram, 이하 ECG)를 이용한 생체인증이 헬스케어 및 핀테크와 맞물려 높은 관심을 받고 있다. 본 연구에서는 기존의 고가이면서 부피가 커 휴대가 불가능한 ECG 측정디바이스가 아닌 소형화된 웨어러블 디바이스를 이용하여 손쉽게 사용자의 ECG 파형을 측정해 사용자 인증을 할 수 있는 ECG 인증 시스템을 구현하였다. 구현된 ECG 인증 시스템은 PQRST 고유 값 식별을 통해 ECG 특징점을 판별하고 이를 이용한 제안된 인증 프로토콜로 사용자 인증이 가능하였다. 최종적으로 성인 남성 다수를 통한 측정 평가를 통해 안정적인 정지 상태에서는 1.73%의 비교적 낮은 타인수락률과 4.14%의 본인거부율을 보였고 움직임이 있는 상태에서는 13.72%의 타인수락률과 21.68%의 높은 본인거부율을 보였다. 활동으로 인해 심박수가 상승한 정지 상태에서는 10.48%의 타인수락률과 11.21%의 본인거부율을 보였다.

• 한국멀티미디어학회논문지
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• 제10권12호
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• pp.1559-1565
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• 2007

The many target-detection methods that use forward-looking infrared (FUR) images can deal with large targets measuring $70{\times}40$ pixels, utilizing their shape features. However, detection small targets is difficult because they are more obscure and there are many target-like objects. Therefore, few studies have examined how to detect small targets consisting of fewer than $30{\times}10$ pixels. This paper presents a small target detection method using clutter rejection with stochastic hypothesis testing for FLIR imagery. The proposed algorithm consists of two stages; detection and clutter rejection. In the detection stage, the mean of the input FLIR image is first removed and then the image is segmented using Otsu's method. A closing operation is also applied during the detection stage in order to merge any single targets detected separately. Then, the residual of the clutters is eliminated using statistical hypothesis testing based on the t-test. Several FLIR images are used to prove the performance of the proposed algorithm. The experimental results show that the proposed algorithm accurately detects small targets (Jess than $30{\times}10$ pixels) with a low false alarm rate compared to the center-surround difference method using the receiver operating characteristics (ROC) curve.

• 대한의용생체공학회:의공학회지
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• 제31권3호
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• pp.177-186
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• 2010

In 3D ultrasound color Doppler imaging (CDI), 8-16 pulse transmissions (ensembles) per each scanline are used for effective clutter rejection and flow estimation, but it yields a low volume acquisition rate. In this paper, we have evaluated three flow estimation methods: autoregression (AR), eigendecomposition (ED), and autocorrelation combined with adaptive clutter rejection (AC-ACR) for a small ensemble size (E=4). The performance of AR, ED and AC-ACR methods was compared using 2D and 3D in vivo data acquired under different clutter conditions (common carotid artery, kidney and liver). To evaluate the effectiveness of three methods, receiver operating characteristic (ROC) curves were generated. For 2D kidney in vivo data, the AC-ACR method outperforms the AR and ED methods in terms of the area under the ROC curve (AUC) (0.852 vs. 0.793 and 0.813, respectively). Similarly, the AC-ACR method shows higher AUC values for 2D liver in vivo data compared to the AR and ED methods (0.855 vs. 0.807 and 0.823, respectively). For the common carotid artery data, the AR provides higher AUC values, but it suffers from biased estimates. For 3D in vivo data acquired from a kidney transplant patient, the AC-ACR with E=4 provides an AUC value of 0.799. These in vivo experiment results indicate that the AC-ACR method can provide more robust flow estimates compared to the AR and ED methods with a small ensemble size.

• 한국군사과학기술학회지
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• 제17권2호
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• pp.175-181
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• 2014

In this paper, we propose a robust clutter pre-thresholding method using background adaptive Threshold Map for the clutter rejection in the complex coastal environment. The proposed algorithm is composed of the use of Threshold Map's and method of its calculation. Additionally we also suggest an automatic decision method of Thresold Map's update. Experimental results on some sets of real infrared image sequence show that the proposed method could remove clutters effectively without any loss of detection rate for the aim target and reduce processing time dramatically.

• Membrane and Water Treatment
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• 제13권3호
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• pp.139-145
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• 2022

Development in advanced separation processes leads to the significant advancement in polymeric membrane preparation methodology. Therefore, present research investigated the preparation and characterization of cellulose acetate membrane by phase inversion separation method to determine optimized operating parameters. Prepared CA membrane's performance was been analyzed in terms of % rejection and flux. Investigation was conducted to study effect of different parameters such as polymer concentration, evaporation rate, thickness of film, coagulation bath properties, temperature of polymer solution and of the coagulation bath etc. CA membrane was fabricated by taking polymer concentration 10wt% and 11wt% with zero second evaporation time and varying film thickness over non-woven polyester fabric. Effect of coagulation bath temperature (CBT) and casting solution temperature were also been studied. The experimental results from SEM showed that the surface morphology had been changed with polymer r concentration, coagulation bath and casting solution temperature, etc. Lower polymer concentration leads to lower precipitation time giving porous membrane. The prepared membrane was tested for advanced waste water treatment of relevant effluent stream in pilot plant to study flux and rejection behavior of the membrane.

• 상하수도학회지
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• 제28권4호
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• pp.397-409
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• 2014

Algal problem in drinking water treatment is being gradually increased by causing deterioration of water supplies therefore, especially taste and odor compounds such as geosmin and 2-MIB occur mainly aesthetic problem by its unpleasant effects resulting in the subsequent onset of complaints from drinking water consumer. Recently, geosmin and 2-MIB are detected frequently at abnormally high concentration level. However, conventional water treatment without advanced water treatment processes such as adsorption and oxidation process, cannot remove these two compounds efficiently. Moreover, it is known that the advanced treatment processes i.e. adsorption and oxidation have also several limits to the removal of geosmin and 2-MIB. Therefore, the purpose of this study was not only to evaluate full scale nanofiltration membrane system with $300m^3/day$ of permeate capacity and 90% of recovery on the removal of geosmin and 2-MIB in spiked natural raw water sources at high feed concentration with a range of approximately 500 to 2,500 ng/L, but also to observe rejection property of the compounds within multi stage NF membrane system. Rejection rate of geosmin and 2-MIB by NF membrane process was 96% that is 4% of passage regardless of the feed water concentration which indicates NF membrane system with an operational values suggested in this research can be employed in drinking water treatment plant to control geosmin and 2-MIB of high concentration. But, according to results of regression analysis in this study it is recommended that feed water concentration of geosmin and 2-MIB would not exceed 220 and 300 ng/L respectively which is not to be perceived in drinking tap water. Also it suggests that the removal rate might be depended on an operating conditions such as feed water characteristics and membrane flux. When each stage of NF membrane system was evaluated relatively higher removal rate was observed at the conditions that is lower flux, higher DOC and TDS, i.e., $2^{nd}$ stage NF membrane systems, possibly due to an interaction mechanisms between compounds and cake layer on the membrane surfaces.

• 한국정보통신학회논문지
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• 제9권7호
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• pp.1607-1615
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• 2005

본 논문은 MLP (multilayer perceptrons) 신경망을 이용하여 필기체 妾자와 비숫자를 인식하거나 기각할 경우의 MLP 구현 방법에 관한 것이다. MLP는 인식률 및 속도, 메모리 요구량 등에 있어서 필기체 숫자인식에 매우 효율적인 인식기로 알려져 있다. 그러나 기존 연구에서의 MLP는 숫자 입력에 대해서의 인식에만 초점이 맞춰져 있으며 비숫자 입력 경우의 인식률, 기각률 및 동작 특성에 대해서는 연구된 바가 거의 없다. 본 논문에서는 숫자와 비숫자가 혼재하는 경우의 MLP 인식기의 구현방법에 대해서 논한다. MLP 인식기는 세 가지 방법으로 구현되며, 세 가지의 오류유형을 정의하여 각 인식 방법의 인식 특성을 분석하였다. 인식 실험은 66,705자의 필기체 숫자와 비숫자를 이용하여 이루어지며, 세가지 오류유형의 측면에서 숫자와 비숫자에 대한 가장 적절한 인식 방법이 논의된다.

• Membrane and Water Treatment
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• 제1권3호
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• pp.171-179
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• 2010

The transport of selected salts of sulphuric acid (cobalt, copper, iron(II), manganese, nickel and zinc sulphate) through an anion-exchange membrane Neosepta-AFN was investigated in a counter-current continuous dialyzer at various salt concentrations and volumetric liquid flow rates. The basic transport characteristics - the rejection coefficient of salt and the permeability of the membrane - were calculated from measurements at steady state. The salt concentration in model mixtures was changed in the limits from 0.1 to 1.0 kmol $m^{-3}$ and the volumetric liquid flow rate of the inlet streams was in the limits from $8{\times}10^{-9}$ to $24{\times}10^{-9}m^3\;s^{-1}$. Under the experimental conditions given, the rejection coefficient of salts tested was in the range from 65% to 94%. The lowest values were obtained for iron(II) sulphate, while the highest for copper sulphate. The maximum rejection of salt was reached at the highest volumetric liquid flow rate and the highest salt concentration in the feed. The permeability ($P_A$) of the Neosepta-AFN membrane for the individual salts was in the range from $0.49{\times}10^{-7}m\;s^{-1}$ to $1.8{\times}10^{-7}m\;s^{-1}$ and it can be described by the following series: $P_{FeSO_4}$ < $P_{NiSO_4}$ < $P_{ZnSO_4}$ < $P_{CoSO_4}$ < $P_{MnSO_4}$ < $P_{CuSO_4}$. The permeability of the membrane was strongly affected by the salt concentration in the feed - it decreased with an increasing salt concentration.

• 한국통신학회논문지
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• 제19권10호
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• pp.2053-2063
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• 1994

최근 HDTV의 지상방송에 대한 관심이 고조되고 있다. HDTV의 지상방송중 동시방송방식(Simulcast)에서는 NTSC 신호와 HDTV 신호간의 간섭현상이 발생한다. 이러한 동일채널 간섭 현상을 제거하기 위해 최근 GA(Grand Alliance)에서는 comb 필터를 사용한 간접제기 시스템을 제시하였다. 그러나, 이 방식은 NTSC 반송파의 주파수 변이에 약한 성능을 보이는 단점이 있다[7]. 따라서, 본 논문에서는 NTSC 반송파의 주파수 변이에도 강인하게 동작하는 동일채널 간섭제거 시스템을 제시한다. 제안하는 간섭제거 시스템은 적응노치필터를 적응동화기와 함께 사용하는 방식이다. 본 논문에서는 NTSC 간섭모델을 이용한 간섭제거기의 성능분석도 다루었다. 모의실험 결과 NTSC 반송파의 주파수 변이가 존재하는 대부분의 경우 제안하는 간접제거기는 기존의 제거기 보다 전체적인 비트오율(BER) 면에서 약 10 정도의 개선이 이루어짐을 확인할 수 있다.

• 간호행정학회지
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• 제21권5호
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• pp.561-574
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• 2015

Purpose: The purpose of this study was to analysis the manuscripts rejected for publication in the Journal of Korean Academy of Nursing Administration during the last three years six months (2012~2015 Jun). Methods: Seventy eight rejected manuscripts were analyzed focusing on manuscripts characteristics, such as rejection rates, year of submission, occupation of first author and corresponding author, number of authors, funding, thesis or dissertation, article type, study participants, number of reviews prior to rejection, and 3rd reviewer. Also reviewers' quantitative evaluation scores and subjective comments were analyzed. Reviewers' subjective comments were analyzed using content analysis methodology. Results: The mean rate for manuscript rejection was 28.9% and for quantitative research, qualitative research, and review papers the quantitative evaluation scores were $2.54{\pm}0.70$, $2.39{\pm}0.69$, and $2.39{\pm}0.69$ out of 5 points, respectively. The most frequent subjective comment on rejected manuscripts was 'lack of rationale for research need'. Conclusion: In this study the characteristics and the reasons for rejecting manuscripts were identified. These findings can be used in developing effective strategies for researchers, reviewers and editors to improve the quality of research and research reviews of nursing administration research.