• Korean Journal of Ecology and Environment
• /
• v.55 no.1
• /
• pp.76-83
• /
• 2022

We attempted to estimate potential habitats of Clithon retropictus and to determine the community structure of benthic macroinvertebrates by presence of C. retropictus. 2016 to 2018 database of "Survey and Assessment of Estuary Ecosystem Health" by the Ministry of Environment were used to identify the distribution site of C. retropictus. The occupancy model was applied to estimate the potential habitat of C. retropictus. Four diversity indices were used to confirm the community structure of benthic macroinvertebrates. C. retropictus was found in the southern coast area and part of the east coast, and this pattern was consistent with previous studies. Additionally, the occupancy model predicted that a potential habitat of C. retropictus could appear in the west coast area. The community structure of benthic macroinvertebrates was relatively high at the site with C. retropictus than the site without C. retropictus. Therefore, the occupancy model can be considered when conserving C. retropictus inhabiting a limited area. Additionally, C. retropictus can be used to the indicator species that can represent the brackish water environment.

• Journal of Space Technology and Applications
• /
• v.3 no.2
• /
• pp.165-198
• /
• 2023

According to the studies recently published through advanced maui optical and space surveillance technologies (AMOS) Conference 2021, LEO conjunction assessment revolves around not on operating satellites but space debris such as rocket bodies and non-operational satellites, hence suggesting a solution through space traffic management. Against this backdrop, the issue of active debris removal (ADR) has emerged to the surface as an international challenge throughout the globe. In step with this, the United Nations General Assembly approved a resolution calling on nations to halt tests of direct-ascent anti-satellites, to which U.S. and twelve other nations included Republic of Korea were original signatories. ADR techniques are also actively being researched in the civil sector, and these commercial services, if successfully developed, could possibly be utilized for military use as well. As such, this paper will help readers' understanding for the current status of ADR techniques, space threat assessments, on-orbit rendezvous and proximity operations by looking at previous cases, reflecting on space-faring nations' ADR techniques and its development probability in relation to space weapons. As a conclusion, this study will propose the needs of developing space propulsion system by understanding Space Maneuver Warfare in preparation for the future space battlefield.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.1A
• /
• pp.75-89
• /
• 2006

This paper presents a practical and realistic Life-Cycle Cost (LCC) optimum design methodology of steel bridges considering time effect of bridge reliability under environmental stressors such as corrosion and heavy truck traffics. The LCC functions considered in the LCC optimization consist of initial cost, expected life-cycle maintenance cost and expected life-cycle rehabilitation costs including repair/replacement costs, loss of contents or fatality and injury losses, road user costs, and indirect socio-economic losses. For the assessment of the life-cycle rehabilitation costs, the annual probability of failure which depends upon the prior and updated load and resistance histories should be accounted for. For the purpose, Nowak live load model and a modified corrosion propagation model considering corrosion initiation, corrosion rate, and repainting effect are adopted in this study. The proposed methodology is applied to the LCC optimum design problem of an actual steel box girder bridge with 3 continuous spans (40 m+50 m+40 m=130 m), and various sensitivity analyses of types of steel, local corrosion environments, average daily traffic volume, and discount rates are performed to investigate the effects of various design parameters and conditions on the LCC-effectiveness. From the numerical investigation, it has been observed that local corrosion environments and the number of truck traffics significantly influence the LCC-effective optimum design of steel bridges, and thus realized that these conditions should be considered as crucial parameters for the optimum LCC-effective design.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.50 no.4
• /
• pp.396-408
• /
• 2023

The purpose of this study was to compare the proximal surface contour, size of contact area, and volume difference before and after restoration in artificial teeth of primary molars during proximal composite resin restoration using different matrix systems. Four types of artificial teeth were restored with composite resin using sectional matrix systems-Palodent V3 Sectional Matrix System and myJunior Kitand a circumferential matrix system-Tofflemire Matrix System-and modeled threedimensionally for analysis. When sectional matrix systems were used, there was a higher probability of concave proximal surface contour and simultaneously greater contact area and volume. This is attributed to the dead soft properties of the matrix band used in sectional matrix systems, which can lead to deformation of the band and hence an excessive amount of resin applied around the contact point. Additionally, the rubber wedge in the sectional matrix system may not help the matrix band fit into the cavity. Therefore, based on the findings of this study, morphological aspects need to be carefully considered for proximal composite resin restoration of primary molars using sectional matrix systems.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.27 no.4
• /
• pp.507-515
• /
• 2024

Microbial forensics is a scientific discipline for analyzing evidence related to biological crimes by identifying the origin of microorganisms. Multiple locus variable number tandem repeat analysis(MLVA) is one of the microbiological analysis methods used to specify subtypes within a species based on the number of tandem repeat in the genome, and advances in next generation sequencing(NGS) technology have enabled in silico anlysis of full-length whole genome sequences. In this paper, we analyzed unknown samples provided by Robert Koch Institute(RKI) through The United Nations Secretary-General's Mechanism(UNSGM)'s external quality assessment exercise(EQAE) project, which we officially participated in 2023. We confirmed that the 3 unknown samples were B. anthracis through nucleic acid isolation and genetic sequence analysis studies. MLVA results on 32 loci of B. anthracis were analysed by using genome sequences obtained from NGS(NextSeq and MinION) and Sanger sequencing. The MLVA typing using short-reads based NGS platform(NextSeq) showed a high probability of causing assembly error when a size of the tandem repeats was grater than 200 bp, while long-reads based NGS platform(MinION) showed higher accuracy than NextSeq, although insertion and deletion was observed. We also showed hybrid assembly can correct most indel error caused by MinION. Based on the MLVA results, genetic identification was performed compared to the 2,975 published MLVA databases of B. anthracis, and MLVA results of 10 strains were identical with 3 unkonwn samples. As a result of whole genome alignment of the 10 strains and 3 unknown samples, all samples were identified as B. anthracis strain A4564 which is associated with injectional anthrax isolates in heroin users.

• Korean Journal of Radiology
• /
• v.25 no.1
• /
• pp.103-112
• /
• 2024

Objective: To investigate the association of ultrasound (US) features of follicular thyroid carcinoma (FTC) with tumor invasiveness and prognosis based on the World Health Organization (WHO) classification and telomerase reverse transcriptase (TERT) promoter mutations. Materials and Methods: This retrospective study included 54 surgically confirmed FTC patients with US images and TERT promoter mutations (41 females and 13 males; median age [interquartile range], 40 years [30-51 years]). The WHO classification consisted of minimally invasive (MI), encapsulated angioinvasive (EA), and widely invasive (WI) FTCs. Alternative classifications included Group 1 (MI-FTC and EA-FTC with wild type TERT), Group 2 (WI-FTC with wild type TERT), and Group 3 (EA-FTC and WI-FTC with mutant TERT). Each nodule was categorized according to the US patterns of the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) and American College of Radiology-TIRADS (ACR-TIRADS). The Jonckheere-Terpstra and Cochran-Armitage tests were used for statistical analysis. Results: Among 54 patients, 29 (53.7%) had MI-FTC, 16 (29.6%) had EA-FTC, and nine (16.7%) had WI-FTC. In both the classifications, lobulation, irregular margins, and final assessment categories showed significant differences (all Ps ≤ 0.04). Furthermore, the incidences of lobulation, irregular margin, and high suspicion category tended to increase with increasing tumor invasiveness and worse prognosis (all Ps for trend ≤ 0.006). In the WHO groups, hypoechogenicity differed significantly among the groups (P = 0.01) and tended to increase in proportion as tumor invasiveness increased (P for trend = 0.02). In the alternative group, punctate echogenic foci were associated with prognosis (P = 0.03, P for trend = 0.03). Conclusion: Increasing tumor invasiveness and worsening prognosis in FTC based on the WHO classification and TERT promoter mutation results were positively correlated with US features that indicate malignant probability according to both K-TIRADS and ACR-TIRADS.

• Safety and Health at Work
• /
• v.15 no.1
• /
• pp.66-72
• /
• 2024

Background: This study examines the relationship between functional disability and work ability in workers affected by low back pain (LBP) through an analysis of correlations between the Oswestry Disability Index (ODI) and Work Ability Index (WAI). The role of personal and work factors on functional disability/work ability levels has also been studied. LBP is the most common musculoskeletal problem and a major disabling health problem worldwide. Its etiology is multifactorial. Multidisciplinary approaches may help reduce the burden of pain and disability and improve job continuity and reintegration at work. Methods: A cohort of 264 patients affected by LBP from an Italian outpatient clinic were included in a clinical diagnostic/therapeutic trial aiming at rehabilitation and return to work through an integrated investigation protocol. Data were collected during the first medical examination using anamnestic and clinical tools. The final sample is composed of 252 patients, 57.1% man, 44.0 % blue collars, 46.4% with the high school degree, 45.6% married. Results: WAI and ODI reported a negative and fair correlation (r = -0.454; p = .000). Workers with acute LBP symptoms have a higher probability of severe disability than those with chronic LBP symptoms. White collars without depressive symptoms reported higher work ability - even in chronic disability conditions-than those with depressive symptoms. Conclusion: The study found that ODI and WAI have a convergent validity and this suggests that the two tools measure capture distinctive aspects of disability related to personal, environmental, and occupational characteristics. The most important and modifiable prognostic factors found for ODI and WAI were depressive symptoms, workday absence, and intensity of back pain. The study also found a mild association between age and ODI. The study's findings highlight the importance of using a multidisciplinary approach to manage and prevent disability due to LBP.

• Journal of Gastric Cancer
• /
• v.24 no.2
• /
• pp.172-184
• /
• 2024

Purpose: The original eCura system was designed to stratify the risk of lymph node metastasis (LNM) after endoscopic resection (ER) in patients with early gastric cancer (EGC). We assessed the effectiveness of a modified eCura system for reflecting the characteristics of undifferentiated-type (UD)-EGC. Materials and Methods: Six hundred thirty-four patients who underwent non-curative ER for UD-EGC and received either additional surgery (radical surgery group; n=270) or no further treatment (no additional treatment group; n=364) from 18 institutions between 2005 and 2015 were retrospectively included in this study. The eCuraU system assigned 1 point each for tumors >20 mm in size, ulceration, positive vertical margin, and submucosal invasion <500 ㎛; 2 points for submucosal invasion ≥500 ㎛; and 3 points for lymphovascular invasion. Results: LNM rates in the radical surgery group were 1.1%, 5.4%, and 13.3% for the low-(0-1 point), intermediate- (2-3 points), and high-risk (4-8 points), respectively (P-fortrend<0.001). The eCuraU system showed a significantly higher probability of identifying patients with LNM as high-risk than the eCura system (66.7% vs. 22.2%; McNemar P<0.001). In the no additional treatment group, overall survival (93.4%, 87.2%, and 67.6% at 5 years) and cancer-specific survival (99.6%, 98.9%, and 92.9% at 5 years) differed significantly among the low-, intermediate-, and high-risk categories, respectively (both P<0.001). In the high-risk category, surgery outperformed no treatment in terms of overall mortality (hazard ratio, 3.26; P=0.015). Conclusions: The eCuraU system stratified the risk of LNM in patients with UD-EGC after ER. It is strongly recommended that high-risk patients undergo additional surgery.

• Korean Security Journal
• /
• no.10
• /
• pp.189-213
• /
• 2005

Risk management should be controlled systematically by effectively evaluating and suggesting countermeasures against the various risks which are followed by the change of the society and environment. These days, enterprise risk management became a new trend in the field. The first step in risk analysis is to recognize the risk factors, that is to verify the vulnerabilities of loss in the security facilities. The second step is to consider the probability of loss in assessing the risk factors. And the third step is to evaluate the criticality of loss. The security manager will determine the assessment grades and then the risk levels of each risk factor, on the basis of the result of risk analysis which includes the assessment of vulnerability, the provability of loss and the criticality. It is of great importance to put the result of risk analysis in mathematical statement for a scientific approach to risk management. Using the risk levels gained from the risk analysis, the security manager can develop a comprehensive and supplementary security plan. In planning the risk management measures to prepare against and minimize the loss, insurance is one of the best loss-prevention programs. However, insurance in and of itself is no longer able to meet the security challenges faced by major corporations. The security manager have to consider the cost-effectiveness, to suggest the productive risk management alternatives by using the security files which contains every information about the security matters. Also he/she have to reinforce the company regulations on security and safety, and to execute education repeatedly on security and risk management. Risk management makes the most efficient before-the-loss arrangement for and after-the-loss continuation of a business. So it is very much important to suggest a best cost-effective and realistic alternatives for optimizing risk management above all, and this function should by maintained and developed continuously and repeatedly.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
• /
• v.18 no.5
• /
• pp.77-90
• /
• 2023

This study aims to investigate the potential of alternative credit assessment through Social Networking Sites (SNS) as a complementary tool to conventional loan review processes. It seeks to discern the impact of SNS usage characteristics and loan product attributes on credit loan repayment. To achieve this objective, we conducted a binomial logistic regression analysis examining the influence of SNS usage patterns, loan characteristics, and personal attributes on credit loan conditions, utilizing data from Company A's credit loan program, which integrates SNS data into its actual loan review processes. Our findings reveal several noteworthy insights. Firstly, with respect to profile photos that reflect users' personalities and individual characteristics, individuals who choose to upload photos directly connected to their personal lives, such as images of themselves, their private circles (e.g., family and friends), and photos depicting social activities like hobbies, which tend to be favored by individuals with extroverted tendencies, as well as character and humor-themed photos, which are typically favored by individuals with conscientious traits, demonstrate a higher propensity for diligently repaying credit loans. Conversely, the utilization of photos like landscapes or images concealing one's identity did not exhibit a statistically significant causal relationship with loan repayment. Furthermore, a positive correlation was observed between the extent of SNS usage and the likelihood of loan repayment. However, the level of SNS interaction did not exert a significant effect on the probability of loan repayment. This observation may be attributed to the passive nature of the interaction variable, which primarily involves expressing sympathy for other users' comments rather than generating original content. The study also unveiled the statistical significance of loan duration and the number of loans, representing key characteristics of loan portfolios, in influencing credit loan repayment. This underscores the importance of considering loan duration and the quantity of loans as crucial determinants in the design of microcredit products. Among the personal characteristic variables examined, only gender emerged as a significant factor. This implies that the loan program scrutinized in this analysis does not exhibit substantial discrimination based on age and credit scores, as its customer base predominantly consists of individuals in their twenties and thirties with low credit scores, who encounter challenges in securing loans from traditional financial institutions. This research stands out from prior studies by empirically exploring the relationship between SNS usage and credit loan repayment while incorporating variables not typically addressed in existing credit rating research, such as profile pictures. It underscores the significance of harnessing subjective, unstructured information from SNS for loan screening, offering the potential to mitigate the financial disadvantages faced by borrowers with low credit scores or those ensnared in short-term liquidity constraints due to limited credit history a group often referred to as "thin filers." By utilizing such information, these individuals can potentially reduce their credit costs, whereas they are supposed to accrue a more substantial financial history through credit transactions under conventional credit assessment system.