• Convergence Security Journal
• /
• v.8 no.4
• /
• pp.173-181
• /
• 2008

Recently, Worm epidemic models have been developed in response to the cyber threats posed by worms in order to analyze their propagation and predict their spread. Some of the most important ones involve mathematical model techniques such as Epidemic(SI), KM (Kermack-MeKendrick), Two-Factor and AAWP(Analytical Active Worm Propagation). However, most models have several inherent limitations. For instance, they target worms that employ random scanning in the network such as CodeRed worm and it was able to be applied to the specified threats. Therefore, we propose the probabilistic of worm propagation based on the Markov Chain, which can be applied to cyber threats such as Mass SQL Injection worm. Using the proposed method in this paper, we can predict the occurrence probability and occurrence frequency for each threats in the entire system.

• Korean Journal of Veterinary Service
• /
• v.32 no.1
• /
• pp.11-18
• /
• 2009

Porcine epidemic diarrhea virus (PEDV), an enveloped single stranded RNA virus in the family Coronaviridae, causes acute viral enteric disease in piglets. Recently outbreaks of porcine epidemic diarrhea (PED) have been rare in Europe but frequent in Asia. In Korea, the increase of PED prevalence is showing specially in postweaning pigs. The purpose of this study was to investigate nucleotide sequence of nucleocapsid protein gene of PEDV field isolates from postweaning pigs in Korea and get more information about the viruses. A total of 15 postweaing pigs clinically suspected of PEDV infection by severe watery diarrhea and dehydration were used in this study. Viral RNA was extracted from small intestines and stools of the pigs. The N gene was amplified by nested RT-PCR, purificated, sequenced, analyzed and then compared with published sequences of other PEDV strains. Three PEDVs were isolated from the suspected postweaning pigs. The N gene of three PEDV field isolates consisted of 483 nucleotides. These PEDV field isolates showed nucleotide sequence homology range from 99.6% to 95% with Chinese strains, from 99.8% to 95.2% with Korean strains, from 97.3% to 95.7% with Japanese strains and from 96.5% to 95.7% with Belgium and British strains. The encoded pritein shared range from 98.8% to 95.6% with Chinese strains, from 99.4% to 95% with Korean strains, from 97.5% to 96.3% with Japanese strains, from 95.6% to 95% with Belgium and British strains. By phylogenetic tree analysis based on nucleotide sequence, three PEDV field isolates were clustered into two groups which were Chinese isolate groups and other Korean isolate groups. These results indicated that some of PEDV field isolates prevailing in Korean postweaning pigs may be associated with those of Chinese strains and other Korean strains.

• Korean Journal of Veterinary Research
• /
• v.56 no.1
• /
• pp.23-28
• /
• 2016

Porcine epidemic diarrhea virus (PEDV), a porcine enteropathogenic coronavirus, causes lethal watery diarrhea in piglets, resulting in large economic losses because of high mortality. In November 2013, PEDV reemerged in Korea, and these outbreaks have since continuously occurred. In the present study, we determined the full-length nucleocapsid (N) gene sequences of three Korean PEDV field isolates collected in 2014-2015. Sequence and phylogenetic analysis of N genes revealed that recent prevalent Korean PEDV isolates were very closely related to the US PEDV isolates in 2013. Interestingly, the phylogenetic tree based on the nucleotide sequencing of the PEDV N gene was similar to the tree topology of the PEDV complete genomes. Therefore, our data provide a better understanding of the genetic diversity and contribute to the accurate diagnosis and development of vaccines against PEDV.

• Convergence Security Journal
• /
• v.21 no.1
• /
• pp.25-31
• /
• 2021

The purpose of this study was to keep the Security Control Center, which operates under a shift system, uninterrupted during the COVID-19 virus epidemic. Security facilities responding to cybersecurity threats are essential security facilities that must be operated 24 hours a day, 365 days a day in real time, and are critical to security operations and management. If security facilities such as infectious disease epidemic, system failure, and physical impact are closed or affected, they cannot respond to real-time cyberattacks and can be fatal to security issues. Recently, there have been cases in which security system facilities cannot be operated, such as the closure of facilities due to the COVID-19 virus epidemic and the availability of security systems due to the rainy season, and other cases need to be prepared. In this paper, we propose a plan to configure a security system facility as a multiplexing facility and operate it as an alternative in the event of a closed situation.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.7
• /
• pp.45-52
• /
• 2019

With the popularity of mobile Internet and smart phones, the domestic digital music access platform has entered a period of rapid development. Existing studies in the academic circle have shown that experience has a positive impact on user perception and loyalty. However, the research on the relationship between brand loyalty, user perception and user experience of Internet products has not received much attention. Starting from the brand loyalty theory and user experience theory, this paper explores the mechanism of user experience, user perception and brand loyalty of digital music access platform. Based on the development status of digital music access platform in China, the purpose is to explore how the user experience of the mainstream digital music access platform can affect Usefulness Perception, Epidemic Perception. And to explore how the Usefulness Perception, Epidemic Perception can affect users' brand loyalty. also further explore the role of users' perception in this process to understand the relationship between brand and user experience. In practical operations, 398 formal questionnaires were issued online to collect first-hand data, and reliability analysis, factor analysis, correlation analysis and hypothesis analysis were carried out successively on the data in the later stage. Through research, it is found that the user experience of digital music access platform has a partial significant impact on the perception and loyalty of applications. The visual presentation and emotional feelings of digital music access platform are positively correlated with the perceived usefulness of applications. The visual presentation and emotional feelings of digital music access platform are positively correlated with the perceived popularity of applications. The e perceived usefulness and perceived popularity of the digital music access platform are positively correlated with the loyalty of the application. Through this research, it has certain guiding significance to the promotion of digital music access platform's brand loyalty degree.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.05a
• /
• pp.404-407
• /
• 2014

Delay Tolerant Network (DTN) is a networking architecture that is designed to solve network problem in unstable and stressed environments using the Store-Carry-Forward method. Different form general networks, DTN does not guarantee the end-to-end connectivity, it is hard for the exiting TCP/IP based protocols to normally work due to the characteristic such as large latency and unstable link connectivity. And the condition that send massage without the information of the destination occurs frequently. Thus, suitable routing protocols for DTN are required and being researched. In this paper, we propose a novel routing protocol for DTN utilizing epidemic and prediction based algorithm to prevent the defect of previously DTN routing protocols such as the absence of the holistic view of the network. Proposed algorithm predicted destination using the mobility information recorded in neighbor node's history and utilize epidemic based algorithm when occurred condition without destination's information. This algorithm is enhanced in terms of delivery ratio, decreases latency and overhead in sparse network such as DTN.

• Journal of Society of Preventive Korean Medicine
• /
• v.24 no.3
• /
• pp.39-47
• /
• 2020

Objectives : The study aimed to investigate the effect of the COVID-19 epidemic on the mental health of elementary and middle school teachers, especially hwabyung, depression, and anxiety. Methods : The participants were teachers of three elementary schools and one middle school in Seoul. The survey was self-reported by online. The questionnaire included hwabyung scale, CES-D, and GAD-7. Results : The survey conducted from November 5th to December 3rd, 2020. A total number of 81 teachers replied to the survey. The hwabyung prevalence was 27.2% by hwabyung symptoms score. The mean hwabyung characteristics score was 30.10±10.55, the mean hwabyung symptoms score was 18.32±12.26. The depression prevalence was 44.4%, mean CES-D was 15.85±11.51. The anxiety prevalence was 43.2%, mean GAD-7 was 5.05±4.53. Conclusions : The survey showed that teachers had a high score of hwabyung, anxiety, and depression in the COVID-19 epidemic. The teachers were in need of help to improve their mental health.

• Environmental and Resource Economics Review
• /
• v.30 no.1
• /
• pp.27-48
• /
• 2021

We extend and modify the canonical epidemiology model of Eichenbaum, Rebelo and Trabandt (2020) to investigate the general equilibrium effects of COVID-19 spread in the Korean economy when vaccine, treatment and social distancing are available. Particularly, we develop a SIR-macro model which considers possibility of moral inattention of the overconfident agents through which people is more likely to be infected. Our model implies that people's decision to cut back on consumption and work reduces the severity of the epidemic and thus exacerbate the size of the economic recession caused by the epidemic. Another finding is that the average 13 weeks to develop the vaccine and treatment will lead to 2% drop of consumption.

• Korean Journal of Veterinary Research
• /
• v.61 no.4
• /
• pp.30.1-30.11
• /
• 2021

From April 2014 to September 2015, 153 piglets from 52 farms in Jeju were diagnosed with porcine epidemic diarrhea (PED). The major PED cases were focused on suckling piglets (144 piglets, 94.1%), particularly in 1-7-day-old piglets. Histopathologically, severe villous atrophy was observed in the small intestine, especially in the jejunum and ileum. The mean villous height to crypt depth ratios of the jejunum and ileum were 1.4:1 and 1.5:1, respectively. The major histopathologic findings of the small intestine were cytoplasmic vacuolation, cuboidalization, squamation, and exfoliation of the mucosal enterocytes in the villi. The cytoplasmic vacuolations in the enterocytes were the most prevalent lesions in the small intestine and were more severe in the ileum than in the jejunum. According to immunohistochemistry methods, the PED virus (PEDV) antigens were presented in the cytoplasms of the enterocytes, and were distributed more prevalently in the ileum than in the jejunum. PEDV antigens were also detected in the colon of 26 piglets (19.5%). Sequence comparison and phylogenetic analysis indicated that 12 PEDV had more than a 98.9% homology with each other. These PEDV strains were highly homologous with the genogroup 2 North American group.

• Korean Journal of Veterinary Service
• /
• v.44 no.4
• /
• pp.291-297
• /
• 2021

Severe outbreaks of porcine epidemic diarrhoea virus (PEDV) have continued to re-emerge worldwide. Because of the high mortality rate of suckling piglets in PEDV outbreaks, the disease causes significant economic losses in the pig industry. The limited pre-existing immunity against this virus is thought to cause an explosive increase in infection in pig farms. This study aimed to evaluate the clinical symptoms of PEDV after intentional exposure (feedback). During the first few days of the outbreak in a breeding pig farm, 14 sows showed watery diarrhoea, and the disease subsequently spread rapidly throughout the barn. Pigs that were intentionally exposed to PEDV (n=251) showed watery diarrhoea (46.6%), reduced appetite (17.5%), and vomiting (6.0%). However, 75 exposed pigs (29.9%) showed no clinical signs of disease. Four weeks after the feedback challenge, 34 sows gave birth to litters of piglets, which survived with no diarrhoea. Five weeks after the start of the outbreak, PEDV was not detected in any of the examined samples, including environmental swabs. Thus, early diagnosis, prompt establishment of herd immunity, and strict application of biosecurity are good practices to reduce the mortality rates among new-born piglets and control economic losses in pig farms showing PEDV outbreaks.