• Journal of the Korean Data and Information Science Society
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• v.22 no.6
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• pp.1017-1028
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• 2011

When it is not easy to decide the credit scoring for some loan applicants, credit evaluation is postponded and reserve to ask a specialist for further evaluation of undecided applicants. This undecided inference is one of problems that happen to most statistical models including the biostatistics and sportal statistics as well as credit evaluation area. In this work, the undecided inference is regarded as a missing data mechanism under the assumption of MNAR, and use the bivariate probit model which is one of sample selection models. Two undecided inference methods are proposed: one is to make use of characteristic variables to represent the state for decided applicants, and the other is that more accurate and additional informations are collected and apply these new variables. With an illustrated example, misclassification error rates for undecided and overall applicants are obtainded and compared according to various characteristic variables, undecided intervals, and thresholds. It is found that misclassification error rates could be reduced when the undecided interval is increased and more accurate information is put to model, since more accurate situation of decided applications are reflected in the bivariate probit model.

• Journal of Intelligence and Information Systems
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• v.28 no.4
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• pp.329-346
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• 2022

Recently, as the market for short form videos (Instagram, TikTok, YouTube) on social media has gradually increased, research using them is actively being conducted in the artificial intelligence field. A representative research field is Video to Shop, which detects fashion products in videos and searches for product images. In such a video-based artificial intelligence model, product features are extracted using convolution operations. However, due to the limitation of computational resources, extracting features using all the frames in the video is practically impossible. For this reason, existing studies have improved the model's performance by sampling only a part of the entire frame or developing a sampling method using the subject's characteristics. In the existing Video to Shop study, when sampling frames, some frames are randomly sampled or sampled at even intervals. However, this sampling method degrades the performance of the fashion product search model while sampling noise frames where the product does not exist. Therefore, this paper proposes a sampling method MF (Missing Fashion items on frame) sampler that removes noise frames and improves the performance of the search model. MF sampler has improved the problem of resource limitations by developing a keyframe mechanism. In addition, the performance of the search model is improved through noise frame removal using the noise detection model. As a result of the experiment, it was confirmed that the proposed method improves the model's performance and helps the model training to be effective.

• Journal of Trauma and Injury
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• v.25 no.3
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• pp.79-86
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• 2012

Purpose: The most common cuase of transfusion for trauma victims in an emergency department is hypovolemic shock due to injury. After an injury to an internal organ of the chest or the abdomen, transfusion is needed to supply blood products and to compensate tissue oxygen transport and bleeding. From the 1990's, there have been some reports that transfusion is one of the major factors causing multiple-organ failure. Thus, as much as possible, tranfusion has been minimized in the clinical setting. This study aims to analyze the prognostic factors for mortality among trauma victims transfused with blood products in an emergency department. Methods: We conducted this study for the year of 2010 retrospectively. The study group included adult trauma victims tranfused with blood products in our ED. The exclusion criteria were discharge against medical advice, and missing follow-up due to transfer to another facility. During the study period, 34 adult trauma victims were enrolled. We compared the clinical variables between survivors and non-survivors. Results: the mean age of the 34 victims was 58.06 years, and males account for 58.5% of the study group. The most-frequently used form transportation was ambulance(119, 55.9%), and the most common injury mechanism was mobile vehicle accidents(67.6%). The mean revised trauma score (RTS) was 5.9, and the mean injury severity score (ISS) was 47.76. The mortality rate in the ED was 58.5%, Comparison of survivors with non-survivors showed statistical differences in injury mechanism, initial SBP, DBP, RTS, ISS, and some laboratory data such as AST, ALT, pH, PO2, HCO3, glucose (p<0.05). Regression analyses showed that mortality among adult trauma victims transfused in the ED correlated with RTS. Conclusion: When an adult trauma victim is transported to the ED and needs a tranfusion, the emergency physician carefully assess the victim by using physiologic data.

• Environmental and Resource Economics Review
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• v.12 no.2
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• pp.347-382
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• 2003

The paper presents available options that Korea can adopt in an effort to promote eco-industrial development in a near future. What is missing and the reasons why Korea is behind the other countries in the area are: 1) Lack of holistic view and the integrated approach toward economy and environment in policy implementation, 2) Lack of understanding, among entrepreneurs, of the concept of productivity per input resource, and the fact that not only labor and capital productivity but also the total productivity enhancement is vital for industry's competitive edge; There has been no driving force in the market to develop economies of system integration to turn industrial wastes to valuable input resources, 3) Unsupportive regulatory system regarding the trade of by products, and 4) Lack of financing and incentive mechanism. 5) Lack of information forum. Regulatory reform should be taken for the direction that in effect increase the price of disposal and motivate firms to seek symbiotic relationship with other firms, and facilitate trade by-product between firms. Financing and incentive mechanism should be introduced in order for the industry to find easy access to the opportunities for organizing the network to transform wastes in negative value to the value added resources. Also information network should be established to provide a market for by-product exchange and public education to improve industry's environmental performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1502-1522
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• 2019

Leakage of secret keys may be the most devastating problem in public key cryptosystems because it means that all security guarantees are missing. The forward security mechanism allows users to update secret keys frequently without updating public keys. Meanwhile, it ensures that an attacker is unable to derive a user's secret keys for any past time, even if it compromises the user's current secret key. Therefore, it offers an effective cryptographic approach to address the private key leakage problem. As an extension of the forward security mechanism in certificate-based public key cryptography, forward-secure certificate-based signature (FS-CBS) has many appealing merits, such as no key escrow, no secure channel and implicit authentication. Until now, there is only one FS-CBS scheme that does not employ the random oracles. Unfortunately, our cryptanalysis indicates that the scheme is subject to the security vulnerability due to the existential forgery attack from the malicious CA. Our attack demonstrates that a CA can destroy its existential unforgeability by implanting trapdoors in system parameters without knowing the target user's secret key. Therefore, it is fair to say that to design a FS-CBS scheme secure against malicious CAs without lying random oracles is still an unsolved issue. To address this problem, we put forward an enhanced FS-CBS scheme without random oracles. Our FS-CBS scheme not only fixes the security weakness in the original scheme, but also significantly optimizes the scheme efficiency. In the standard model, we formally prove its security under the complexity assumption of the square computational Diffie-Hellman problem. In addition, the comparison with the original FS-CBS scheme shows that our scheme offers stronger security guarantee and enjoys better performance.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.4
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• pp.483-494
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• 2023

This report presents two cases concerning strategies for improving denture retention in pediatric patients with oligodontia caused by hypohidrotic ectodermal dysplasia (HED). Both patients presented with multiple missing teeth, conical canines, alveolar bone atrophy, and a skeletal Class III tendency. In the first case, a modified form of conical-crown-retained denture was used to cover the canines. This approach was carried out without tooth extraction or coping. In the second case of severe alveolar bone resorption and a distally tilted lower left canine, the tooth was restored with a hybrid ceramic crown. It was subsequently converted into a clasp-retained removable partial denture, utilizing a suction mechanism. Both patients are currently receiving regular check-ups for the maintenance of their prosthetic appliances and the evaluation of their growth patterns. This study presents innovative prosthetic treatment methods for pediatric patients with HED who have inadequate denture retention.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1857-1862
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• 2016

Human activity recognition using depth information is an emerging and challenging technology in computer vision due to its considerable attention by many practical applications such as smart home/office system, personal health care and 3D video games. This paper presents a novel framework of 3D human body detection, tracking and recognition from depth video sequences using spatiotemporal features and modified HMM. To detect human silhouette, raw depth data is examined to extract human silhouette by considering spatial continuity and constraints of human motion information. While, frame differentiation is used to track human movements. Features extraction mechanism consists of spatial depth shape features and temporal joints features are used to improve classification performance. Both of these features are fused together to recognize different activities using the modified hidden Markov model (M-HMM). The proposed approach is evaluated on two challenging depth video datasets. Moreover, our system has significant abilities to handle subject's body parts rotation and body parts missing which provide major contributions in human activity recognition.

• Korea-Australia Rheology Journal
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• v.21 no.1
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• pp.47-58
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• 2009

We have investigated the transient behavior of 1D fully developed Poiseuille viscoelastic flow under finite pressure gradient described by the Oldroyd-B and Leonov constitutive equations. For analysis we employ a simple $2^{nd}$ order discretization scheme such as central difference for space and the Crank-Nicolson for time approximation. For the analysis of the Oldroyd-B model, we also apply the analytical solution, which is obtained again in this work in terms of elementary solution procedure simpler than the previous one (Waters and King, 1970). Both models demonstrate qualitatively similar solutions, but their eventual steady flowrate exhibits noticeable difference due to the absence or presence of shear thinning behavior. In the inertialess flow, the flowrate instantaneously attains a large value corresponding to the Newtonian creeping flow and then decreases to its steady value when the applied pressure gradient is low. However with finite liquid density the flow field shows severe fluctuation even accompanying reversals of flow directions. As the assigned pressure gradient increases, the flowrate achieves its steady value significantly higher than its value during oscillations after quite long period of time. We have also illustrated comparison between 1D and 2D results and possible mechanism of complex 2D flow rearrangement employing a previous solution of [mite element computation. In addition, we discuss some mathematical points regarding missing boundary conditions in 2D modeling due to the change of the type of differential equations when varying from inertialess to inertial flow.

• The Journal of the Acoustical Society of Korea
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• v.6 no.1
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• pp.39-47
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• 1987

It is well-known that analogizing a dynamic system to an equivalent circuit is a powerful tool on the analysis of the system. In this paper, an equivalent circuit of the piano has been constructed by the structural and acoustical analysis to visualize the sounding mechanism. Utilizing the mechanical reactance curve of the soundboard, a new method of reducing che inharmonicity in low frequency range has been built. With this method, by only choosing the proper excitation point on the soundboard, it will be possible to minimize the inharmonicity and thus to obtain mellow bass tone. It is shown that the missing fundamental in the lowest scale range results predominatly from the fact that the radiation impedance in such low frequencies is nearly pure reactive.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1477-1480
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• 2006

The 63-amino-acid-encoding afsR2 is a global antibiotics-stimulating regulatory gene identified from the chromosome of Streptomyces lividans. To dissect a putative functional domain in afsR2, several afsR2-derivative deletion constructs were generated and screened for the loss of actinorhodin-stimulating capability. The afsR2-derivative construct missing a 50-bp C-terminal region significantly lost its actinorhodin-stimulating capability in S. lividans. In addition, site-directed mutagenesis on amino acid positions of #57-#61 in a 50-bp C-terminal region, some of which are conserved among known Sigma 70 family proteins, significantly changed the AfsR2's activity. These results imply that the C-terminal region of AfsR2 is functionally important for antibiotics-stimulating capability and the regulatory mechanism might be somehow related to the sigma-like domain present in the C-terminal of AfsR2.