• Title/Summary/Keyword: maximum-likelihood

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Monitoring Culicine Mosquitoes (Diptera: Culicidae) as a Vector of Flavivirus in Incheon Metropolitan City and Hwaseong-Si, Gyeonggi-Do, Korea, during 2019

  • Bahk, Young Yil;Park, Seo Hye;Kim-Jeon, Myung-Deok;Oh, Sung-Suck;Jung, Haneul;Jun, Hojong;Kim, Kyung-Ae;Park, Jong Myong;Ahn, Seong Kyu;Lee, Jinyoung;Choi, Eun-Jeong;Moon, Bag-Sou;Gong, Young Woo;Kwon, Mun Ju;Kim, Tong-Soo
    • Parasites, Hosts and Diseases
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    • v.58 no.5
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    • pp.551-558
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    • 2020
  • The flaviviruses are small single-stranded RNA viruses that are typically transmitted by mosquitoes or tick vectors and are etiological agents of acute zoonotic infections. The viruses are found around the world and account for significant cases of human diseases. We investigated population of culicine mosquitoes in central region of Korean Peninsula, Incheon Metropolitan City and Hwaseong-si. Aedes vexans nipponii was the most frequently collected mosquitoes (56.5%), followed by Ochlerotatus dorsalis (23.6%), Anopheles spp. (10.9%), and Culex pipiens complex (5.9%). In rural regions of Hwaseong, Aedes vexans nipponii was the highest population (62.9%), followed by Ochlerotatus dorsalis (23.9%) and Anopheles spp. (12.0%). In another rural region of Incheon (habitat of migratory birds), Culex pipiens complex was the highest population (31.4%), followed by Ochlerotatus dorsalis (30.5%), and Aedes vexans vexans (27.5%). Culex pipiens complex was the predominant species in the urban region (84.7%). Culicine mosquitoes were identified at the species level, pooled up to 30 mosquitoes each, and tested for flaviviral RNA using the SYBR Green-based RT-PCR and confirmed by cDNA sequencing. Three of the assayed 2,683 pools (989 pools without Anopheles spp.) were positive for Culex flaviviruses, an insect-specific virus, from Culex pipiens pallens collected at the habitats for migratory birds in Incheon. The maximum likelihood estimation (the estimated number) for Culex pipiens pallens positive for Culex flavivirus was 25. Although viruses responsible for mosquito-borne diseases were not identified, we encourage intensified monitoring and long-term surveillance of both vector and viruses in the interest of global public health.

PCR-based markers to select plastid genotypes of Solanum acaule (Solanum acaule 색소체 유전자형 선발을 위한 특이적 분자마커 개발)

  • Park, Tae-Ho
    • Journal of Plant Biotechnology
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    • v.49 no.3
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    • pp.178-186
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    • 2022
  • The tetraploid Solanum acaule is a wild potato species from Bolivia widely used for potato breeding because of its diverse attractive traits, including resistance to frost, late blight, potato virus X, potato virus Y, potato leafroll virus, potato spindle tuber viroid, and cyst nematode. However, the introgression of useful traits into cultivated potatoes via crossing has been limited by differences in endosperm balance number between species. Somatic fusion could be used to overcome sexual reproduction barriers and the development of molecular markers is essential to select proper fusion products. The chloroplast genome of S. acaule was sequenced using next-generation sequencing technology and specific markers for S. acaule were developed by comparing the obtained sequence with those of seven other Solanum species. The total length of the chloroplast genome is 155,570 bp, and 158 genes were annotated. Structure and gene content were very similar to other Solanum species and maximum likelihood phylogenetic analysis with 12 other species belonging to the Solanaceae family revealed that S. acaule is very closely related to other Solanum species. Sequence alignment with the chloroplast genome of seven other Solanum species revealed four InDels and 79 SNPs specific to S. acaule. Based on these InDel and SNP regions, one SCAR marker and one CAPS marker were developed to discriminate S. acaule from other Solanum species. These results will aid in exploring evolutionary aspects of Solanum species and accelerating potato breeding using S. acaule.

Molecular authentication of Lepidii seu Descurainiae Semen by the development of matK amplification primers and analysis of sequences (matK 증폭용 primer 개발 및 염기서열 분석을 통한 정력자(葶藶子) 유전자 감별)

  • Moon, Byeong Cheol;Kim, Wook Jin;Yang, Sungyu;Park, Inkyu;Yeo, Sang Min;Noh, Pureum
    • The Korea Journal of Herbology
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    • v.33 no.3
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    • pp.25-35
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    • 2018
  • Objectives : Lepidii seu Descurainiae Semen has been frequently adulterated with the seeds of several inauthentic plant species. However, the accurate identification of these plant seeds is very difficult. To develop a reliable genetic authentication tool for Lepidii seu Descurainiae Semen, we analyzed matK sequence. Methods : To obtain the matK sequences of plant materials, genomic DNA was extracted from 24 samples and PCR amplification was carried out using matK-AF/matK-8R universal primer set and matK-LDSF/matK-LDSR primer set. For identifying species-specific nucleotides and phylogenetic analysis, matK regions were sequenced and comparatively analyzed by the ClustalW and Maximum Likelihood method. Results : We developed a new primer set to amplify matK region in Lepidii seu Descurainiae Semen and closely related plant samples. From the comparative analysis of matK sequences, we identified species-specific marker nucleotides for D. sophia, L. apetalum, L. latifolium, E. cheiranthoides, E. macilentum, and D. nemorosa, respectively. Furthermore, phylogenetic analysis revealed clear classification depending on the species. These results indicated that the matK sequence obtained a new primer set in this study was useful to identify Lepidii seu Descurainiae Semen in species level. Conclusions : We developed a primer set and identified species-specific marker nucleotides enough to distinguish authentic Lepidii seu Descurainiae Semen and adulterants at the species level based on the matK sequences. These genetic tool will be useful to prevent adulteration and to standardize the quality of Lepidii seu Descurainiae Semen.

Performance Evaluation of Octonion Space-Time Coded Physical Layer Security in MIMO Systems (MIMO 시스템에서 옥토니언 시공간 부호를 이용한 물리계층 보안에 대한 성능 분석)

  • Young Ju Kim;BeomGeun Kwak;Seulmin Lim;Cheon Deok Jin
    • Journal of Broadcast Engineering
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    • v.28 no.1
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    • pp.145-148
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    • 2023
  • Open-loop Octonion space-time block code for 4 transmit antenna system is considered and random phases are applied to 4 transmit antennas for physical layer security. When an illegal hacker estimates the random phases of 1 through 4 transmit antennas with maximum likelihood (ML), this letter analyzes the bit error rate (BER) performances versus signal-to-noise ratio (SNR). And the Octonion code in the literature[1] does not have full orthogonality so, this letter employs the perfect orthogonal Octonion code. When the hacker knows that the random phases are 2-PSK constellations and he should estimate all the 4 random phases, the hacking is impossible until 100dB. When the hacker possibly know that some of the random phases, bit error rate goes down to 10-3 so, the transmit message could be hacked.

A Short Review for the Estimation Method of Intrinsic Rate of Natural Increase According to the Setting of Initial Age for the Study Cohort in the Lotka Life Table (로트카 생명표에서 연구 집단의 초기연령 설정에 따른 내적자연증가율 추정방법에 대한 고찰)

  • Dong-soon, Kim
    • Korean journal of applied entomology
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    • v.61 no.4
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    • pp.549-554
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    • 2022
  • Life table-related studies in insect ecology have been an interesting topic for insect researchers. Two calculation methods are commonly applied to estimate the intrinsic rate of natural increase (rm) in the life table statistics. The first method is to estimate an approximate rm by dividing the natural logarithm of the net reproductive rate (R0) by mean generation time (T) (namely mean generation time-based method). Another approach is to apply the Lotka-Euler equation derived from the population growth equation of Lotka-Volterra to estimate accurate rm using the maximum likelihood method (Lotka-Euler equation-based method). In the latter case, there is a difference in the estimated rm value when the initial age class of the target cohort was set to "0" or "1", which confused the application. In this short review, a brief history of the calculation process of the life table was reviewed. It was again confirmed in the Lotka-Euler equation-based method that the form of $\sum\limits_{x=1}^{w}e^{-rx}l_xm_x=1$ should be applied to estimate rm when the first age class was set to zero, while the form of $\sum\limits_{x=0}^{w}e^{-r(x+1)}l_xm_x=1$ when set to one.

First Report of Tomato Spotted Wilt Virus in Oxypetalum coeruleum in Korea (옥시페탈룸에서 발생한 토마토반점위조바이러스 국내 첫 보고)

  • Eseul, Baek;Peter, Palukaitis;Ju-Yeon, Yoon
    • Research in Plant Disease
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    • v.28 no.4
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    • pp.231-236
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    • 2022
  • Oxypetalum coeruleum, commonly known as Tweedia, is a perennial herbaceous plant of the Apocynaceae family native to southern Brazil and Uruguay. Tweedia plants are grown as one of the most popular ornamental flowers for floral arrangement in Korea. In May 2021, several tweedia plants in a single greenhouse in Gimje, Jeollabuk-do were found to show virus-like symptoms including necrotic rings, vein-clearing, chlorotic mottle, and mosaic on the leaves, and necrosis on the stems. Here, we have identified tomato spotted wilt virus (TSWV) in symptomatic tweedia leaves by applying high-throughput RNA sequencing. In the result, a single infection by TSWV was verified without mixed infections of different virus species. To confirm the presence of TSWV, a reverse transcription polymerase chain reaction was performed with a specific primer set to the N gene of TSWV. The complete genomic sequence of L, M, and S segments of TSWV 'Oxy' isolate were determined and deposited in GenBank under accession numbers LC671525, LC671638, and LC671639, respectively. In the phylogenetic tree analysis by maximum likelihood method, 'Oxy' isolate showed a high relationship with TSWV 'Gumi' isolate from Gerbera jamesonii in Gyeongsangbuk-do, Korea; for all three RNA segments. To our knowledge, this is the first report of TSWV infection of O. coeruleum in Korea.

The Effect of CSR Motivation of K-Beauty Brands on CSR Authenticity and Brand Trust -Focusing on Comparison of Korean and Chinese Consumers- (K-뷰티 브랜드의 CSR동기가 CSR 진정성과 브랜드 신뢰에 미치는 영향 -한·중 소비자 비교를 중심으로-)

  • Sun-Joo Lee;Yun-Hee Jeong
    • Journal of the Korean Applied Science and Technology
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    • v.40 no.2
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    • pp.210-222
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    • 2023
  • This study conducted a comparative study using Korean and Chinese consumer data to confirm the impact of K-beauty brand's CSR motivation on CSR authenticity and brand trust, and the effect of CSR authenticity and brand trust on brand support. Of the collected data, 392 copies were used for verification and analyzed using a two-step approach and maximum likelihood measure. As a result of the study, it was found that value-driven, stakeholder-driven, and strategic motivations, excluding egoistic motivations, had a positive effect on CSR authenticity and brand trust. In addition, CSR authenticity had a positive effect on brand trust, which was found to support the brand. As a result of comparing Korean and Chinese consumers, it was found that CSR motives in both countries affect authenticity and brand trust, but Chinese consumers showed higher results in more areas than Korean consumers. These results show that K-beauty brands in order to expand the Chinese market, it has implications that it is necessary to understand Chinese consumers and strengthen the CSR motivation strategy they pursue.

Impact of U.S. Trade Pressure on Korean Domestic Automobile Industry: Centering on Trade Protectionism Expansion (미국의 통상압력에 따른 국내 자동차산업 파급효과: 보호무역주의 확대를 중심으로)

  • Choi, Nam-Suk
    • Korea Trade Review
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    • v.43 no.5
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    • pp.25-45
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    • 2018
  • This paper estimates the export losses of the Korean domestic automobile industry due to US trade pressure and its economic ripple effects. Using the HS 6 digit tariff and export data from 2010 to 2017, this paper estimates the tariff elasticity of Korea's US automobile exports against a US tariff increase by applying the Poisson Pseudo maximum likelihood estimation method. After estimating Korea's export losses to the US in three trade pressure scenarios, we estimate its impact on Korean domestic production, value-added and job creation by applying the tariff impact accumulation model based on the industry input-output analysis. Empirical results show that the impact of 25% global tariff by the US on the Korean domestic economy is estimated to result in $30.8 billion in export losses for the five years from 2019 to 2023, about 300 thousand job losses, 88.0 trillion in production inducement losses, and 24.0 trillion in value-added inducement losses. The impacts of withdrawal of the automobile tariff concession are estimated at $4.27 billion export losses and 41.7 thousand job losses. A 15% tariff rate on automobile parts for 3 years is estimated to result in $1.93 billion export losses and 18.7 thousand job losses.

An Acoustic Event Detection Method in Tunnels Using Non-negative Tensor Factorization and Hidden Markov Model (비음수 텐서 분해와 은닉 마코프 모델을 이용한 터널 환경에서의 음향 사고 검지 방법)

  • Kim, Nam Kyun;Jeon, Kwang Myung;Kim, Hong Kook
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.8 no.9
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    • pp.265-273
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    • 2018
  • In this paper, we propose an acoustic event detection method in tunnels using non-negative tensor factorization (NTF) and hidden Markov model (HMM) applied to multi-channel audio signals. Incidents in tunnel are inherent to the system and occur unavoidably with known probability. Incidents can easily happen minor accidents and extend right through to major disaster. Most incident detection systems deploy visual incident detection (VID) systems that often cause false alarms due to various constraints such as night obstacles and a limit of viewing angle. To this end, the proposed method first tries to separate and detect every acoustic event, which is assumed to be an in-tunnel incident, from noisy acoustic signals by using an NTF technique. Then, maximum likelihood estimation using Gaussian mixture model (GMM)-HMMs is carried out to verify whether or not each detected event is an actual incident. Performance evaluation shows that the proposed method operates in real time and achieves high detection accuracy under simulated tunnel conditions.

Reexamination of Coach-Athlete Relationship Maintenance Scale in Pro Baseball (프로야구 코치-선수관계 유지 척도 재검증)

  • Huh, Jin-Young;Choi, Hun-Hyuk
    • 한국체육학회지인문사회과학편
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    • v.55 no.1
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    • pp.221-233
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    • 2016
  • The purpose of this study was to prove a development and initial validation of the korean version of coach-athlete relationship maintenance scale that originated from the work of Rhind & Jowett(2012) in pro baseball. The items were then administered to 132 Participants(29 coaches and 103 athletes) completed the questionnaires of the coach-athlete relationship maintenance in First preliminary investigation. Maximum likelihood estimate was used to identify the latent underlying structure. In order to verify the validity of Korean version of coach-athlete relationship maintenance was administered to an independent sample of 273 coaches and athletes. Pro baseball coach-athlete relationship maintenance is consisted of six factors(25 items) with conflict management, motivational, preventative, openness/assurance, support, and social network. SPSS18.0 and AMOS16.0 were used to analyze the exploratory factor analysis, confirmatory factory analysis and internal consistency, test-retest with bootstrapping using of the data in this study. The results of the pro baseball coach-athlete relationship maintenance scale had six factors with 25 items, and each six factor was positively correlated. Overall, this study verified pro baseball coach-athlete relationship maintenance questionnaire. Thus, suggest that path of comparing the differences between the first division and farm team by using the test of the structural model invariance across the groups.