• Journal of applied mathematics & informatics
• /
• 제39권5_6호
• /
• pp.895-918
• /
• 2021

Human African Trypanosomiasis (HAT) also known as sleeping sickness, is a neglected tropical vector borne disease caused by trypanosome protozoa transmitted by bites of infected tsetse fly. The basic reproduction number, R₀ derived using the next generation matrix method which shows that the disease persists in the population if the value of R₀ > 1. The numerical simulations of optimal control model carried out to determine the control strategy that can combat HAT under the minimum cost. The results indicate that, the use of both education campaign, treatment and insecticides are more efficient and effective to eliminate HAT in African community but too costly. Furthermore, the cost-effectiveness of the control measures (education campaign, treatment and insecticides) were determined using incremental cost-effectiveness ratio (ICER) approach and the results show that, the use of education and treatment of infected people as the best cost effective strategy compared to other strategies.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제27권4호
• /
• pp.281-295
• /
• 2023

This study aims to establish and analyze a mathematical model for the transmission dynamics of male adolescent smoking and to determine an optimal control strategy to reduce male adolescent smoking. We consider three groups in the population: smokers, non-smokers, and temporary nonsmokers. In our model to which optimal control theory was applied, the number of smokers decreased sharply and the number of non-smokers increased significantly. Our simulation results under various control scenarios reveal that integrated control measures(such as prevention, education, and treatment) may be necessary to reduce the growth rate of adolescent smoking. Moreover, we concluded that efforts to encourage current smokers and temporary quitters to quit should be sustained longer than efforts to reduce the rate at which nonsmokers become smokers through smoking prevention education.

• Asian-Australasian Journal of Animal Sciences
• /
• 제17권2호
• /
• pp.283-300
• /
• 2004

Currently commercial dry sows are housed in individual stalls and subject to restricted feeding. These sows often show stereotypic behaviours which increase their maintenance energy requirement. Group housing is desirable to improve animal welfare and public perception. However, under restricted feeding systems, group-housed dry sows are also aggressive. The feed intake of these sows is variable, depending on their social rank, which results in different milk production and variable piglet performance. These problems can be solved by ad libitum feeding systems, but the large capacity of intake by dry sows will not allow this feeding system to be practical as high feeding level during pregnancy can reduce reproduction performance of sows. Current research indicates that feeding high fibre diets to dry sows enables sows to be fed ad libitum, but the effect of dietary fibre on feed intake and nutrient utilisation is dependent on the quality of fibre sources. Most research has focused on sugar beet pulp, straw, lucerne meal and by-products, but there is a need to identify and evaluate some widely available and cheap fibre materials and feed grains for developing the best strategy to control nutrient intake of dry sows while feeding ad libitum.

• 한국동물생명공학회지
• /
• 제34권1호
• /
• pp.35-39
• /
• 2019

This study aimed to recover the ovarian function through in vitro culture of preantral follicles from aged mice. First, we isolated the preantral follicles from ovaries of sixty-seven-week old B6D2F1 mice with decreased fecundity to know how many follicles were present in them, which was 6 preantral follicles including 2 primary, 2 early secondary and late secondary follicles from 8 aged mice. It was confirmed that a few follicles (~2) were present in aged mice through histological analysis compared to adult mice as control. The 9 days of in vitro culture of preantal follicles showed in vitro growth and induced maturation after treatment with hCG (2.5 IU/mL) and EGF (5 ng/mL). Cumulus cells in the cumulus-oocyte complexes (COCs) were removed using hyaluronidase and oocytes at the germinal vesicle (GV) and GV breakdown (GVBD) were obtained from preantral follicle culture of aged mice in vitro. In conclusion, these observations demonstrated that there still were a few preantral follicles in the ovaries of 67 week-old mice, which we were able to culture in vitro and oocytes were obtained from them. This study proposed an in vitro culture system using preantral follicle as a therapeutic strategy for fertility preservation in humans for assisted reproductive medicine.

• 한국전자파학회논문지
• /
• 제20권8호
• /
• pp.746-752
• /
• 2009

본 논문에서는 진화 알고리즘을 이용하여 U형 슬롯을 갖는 433 MHz, 912 MHz 및 2.45 GHz의 삼중 대역 PIFA(Planar Inverted-F Antenna)를 설계할 수 있는 프로그램 구현에 대해 다룬다. 일반적으로 U형 슬롯의 넓이와 길이에 따라 개구형 공진 주파수를 결정할 수 있으나, 두 개의 U형 슬롯의 영향으로 공진 주파수가 변화하기 때문에 진화 알고리즘을 이용한 최적 설계 프로그램을 통하여 최적의 U형 슬롯의 넓이와 길이를 구하였다. 변이와 재생산의 반복 과정을 통해 설계 목표에 적합한 설계 변수 값을 찾는 진화 알고리즘을 자동화하기 위하여 상용 전자장 해석 프로그램과 최적 설계 프로그램간의 연동 인터페이스를 구축하였다. 구현한 최적 설계 프로그램을 통한 삼중 대역 PIFA 시뮬레이션 결과는 430 MHz, 910.5 MHz 및 2.458 GHz의 공진 주파수를 갖는다.

• Fisheries and Aquatic Sciences
• /
• 제14권1호
• /
• pp.22-30
• /
• 2011

Vitellogenin (Vg) is the precursor of vitellin (Vn), which is the major yolk protein in nearly all oviparous species, including fish, amphibians, reptiles, and most invertebrates. It is one of the most important factors during reproduction, and numerous studies have shown that Vg genes are markers of the reproductive cycle and effecter genes induced by endocrine-disrupting chemicals (EDCs). Previously, we isolated two distinct cDNAs encoding vitellogenin homologs Pj-Vg1 and Pj-Vg2 from Pandalus shrimp Pandalopsis japonica. In this study, full-length genomic sequences of Pj-Vg1 and Pj-Vg2 were determined using a PCR-based genome walking strategy. Isolated Pj-Vg1 and Pj-Vg2 genes were 11,910 and 11,850 bp long, respectively. Both Pj-Vg genes had 15 exons and 14 introns, and the splicing sites were also the same, suggesting that they arose via gene duplication. The similar structural characteristics of decapod Vg genes suggest that they are all orthologs that evolved from the same ancestral gene. Analysis of Pj-Vg1 and Pj-Vg2 expression revealed that the relative copy numbers of Pj-Vg1 and Pj-Vg2 were similar in the hepatopancreas, whereas Pj-Vg2 transcripts were also detected in the ovary. Expression of both Pj-Vg genes was induced in hepatopancreas of mature individuals, whereas only Pj-Vg2 transcripts were upregulated in the ovaries from mature animals, suggesting that both Pj-Vgs are important for oocyte development. A strong positive correlation was found between Pj-Vg1 and Pj-Vg2 transcripts in the same individual, indicating they are under the same control mechanisms. Additionally, a positive correlation was found between ovarian and hepatopancreatic Pj-Vg2 transcripts, suggesting that its dual expression is regulated by similar physiological conditions. Knowledge of the similarities and differences between the two vitellogenin-like genes, Pj-Vg1 and Pj-Vg2, would help us to understand their roles in reproduction and other physiological effects.

• Journal of Veterinary Science
• /
• 제25권3호
• /
• pp.43.1-43.13
• /
• 2024

Importance: Haemaphysalis longicornis is an obligate blood-sucking ectoparasite that has gained attention due its role of transmitting medically and veterinary significant pathogens and it is the most common tick species in Republic of Korea. The preferred strategy for controlling ticks is a multi-antigenic vaccination. Testing the efficiency of a combination antigen is a promising method for creating a tick vaccine. Objective: The aim of the current research was to analyze the role of subolesin and enolase in feeding and reproduction of H. longicornis by gene silencing. Methods: In this study, we used RNA interference to silence salivary enolase and subolesin in H. longicornis. Unfed female ticks injected with double-stranded RNA targeting subolesin and enolase were attached and fed normally on the rabbit's ear. Real-time polymerase chain reaction was used to confirm the extent of knockdown. Results: Ticks in the subolesin or enolase dsRNA groups showed knockdown rates of 80% and 60% respectively. Ticks in the combination dsRNA (subolesin and enolase) group showed an 80% knockdown. Knockdown of subolesin and enolase resulted in significant depletion in feeding, blood engorgement weight, attachment rate, and egg laying. Silencing of both resulted in a significant (p < 0.05) reduction in tick engorgement, egg laying, egg hatching (15%), and reproduction. Conclusions and Relevance: Our results suggest that subolesin and enolase are an exciting target for future tick control strategies.

• 마케팅과학연구
• /
• 제20권2호
• /
• pp.219-230
• /
• 2010

数字内容在给公司带来机遇和挑战的同时也极大的改变了我们的生活. 创意企业整合视频, 图片, 文本和数据进行数字化过的音频, 开发新产品或服务, 创作数字经验推广自己的品牌. 大多数有关数字内容的文献是关于基本概念或者营销的发展. 其实, 比起普通产品或服务的传统价值链, 数字内容产业似乎有更多的潜在价值. 因为相当多的数字内容是免费的, 价格, 作为信息的质量或价值的指标, 不是必须被感知的(Rowley 2008). 很显然, 当前数字内容的主题是 "价值" 和关于消费者对数字内容的感知价值的研究. 本文讨论了体验价值在消费者评估数字内容时的优势. 本文在对数字内容 "价值" 的理解方面有两个不同但是相关的贡献. 第一, 基于数字内容与普通产品和服务的比较, 本文提出了两个关键特点使得体验战略适合数字内容: 无形和接近于零的再造成本. 最重要的是, 基于对公司的理想化的价值和客户的感知价值之间的差异的讨论, 本文强调了数字内容的价格和定价与普通产品和服务的不同. 无形的结果是, 价格可能并不反映顾客感知价值. 另外, 数字内容的成本处在发展阶段可能非常高但再造会大幅缩水. 而且, 由于前面提到的价值鸿沟, 这个价格政策改变因不同的数字内容而不同. 例如, 平价战略通常用于电影和音乐(Magiera 2001;Netherby 2002), 而有持续的需求的数字内容如在线游戏和杀毒软件的问题牵涉到一个更复杂的效用和极具竞争力的价格水平. 数字内容企业必须探索各种各样的策略来克服这个缺口. 对于广告, 形象, 口碑等常用的市场战略和他们对顾客感知价值的影响的研究变得至关重要. 中国数字内容产业正变得越来越国际化, 并引起了具有各自竞争优势的国家和地区的关注. 2008-2009中国数字内容产业年度发展报告(CCIDConsulting 2009)表明, 在国内需求和政府政策的大力支持下, 中国数字内容产业在2008年保持了大约30%的快速增长, 表明了这个产业在明显的初期扩张阶段. 在中国, 需要更新的杀毒软件和其他软件程序使用季度定价政策. 用户可以免费下载试用版, 用6个月或一年. 如果他们更久的使用, 连续的付款方式是必要的. 他们在试用阶段检测数字内容的优良度, 决定是否要付继续使用. 对于中国的音乐和电影工业的发展战略, 体验最初没有被广泛的应用, 虽然其他国家的公司注意到体验的重要性并探索了相关的战略(如客户在下载前有好几秒可以免费听听音乐). 由于上述原因, 杀毒软件在中国可以代表数字内容产业而且在中国杀毒市场探索了体验价值在顾客的数字内容感知价值中的优势. 为了提高调查数据的可靠性, 该研究集中在那些有使用杀毒软件经验的人群. 实证结果显示, 体验价值对顾客对数字内容的感知价值有积极的影响. 换句话说, 因为数字内容是无形的, 再造成本几乎为零, 客户的评估是根据他们的体验. 另外, 形象和口碑不产生积极的影响, 只对体验价值有影响. 这就是说, 数字内容价值链不同于普通产品或服务. 体验价值有显著的优势并调节形象和口碑对感知价值的作用. 这个研究结果有助于了解为什麽在发展中国家存在免费的数字内容下载. 客户只有通过体验它才可以感知数字内容的价值. 这也是为什么政府如此扶持发展数字内容. 其他发展中国家在起步阶段的数字内容企业可以借鉴这里的建议. 另外, 基于体验战略的优势, 公司应该更努力投资于客户的体验. 由于数字内容的特点和价值鸿沟的存在, 顾客只有经历了他们真正想要的才能感知更多的无形的数字内容的价值. 而且, 因为再造成本近乎为零, 公司可以使用体验战略, 以提高客户对数字内容的理解.

• Journal of Electrical Engineering and Technology
• /
• 제1권4호
• /
• pp.435-447
• /
• 2006

This paper presents an application of the parallel Adaptive Evolutionary Algorithm (AEA) to search an optimal solution of the service restoration in electric power distribution systems, which is a discrete optimization problem. The main objective of service restoration is, when a fault or overload occurs, to restore as much load as possible by transferring the de-energized load in the out of service area via network reconfiguration to the appropriate adjacent feeders at minimum operational cost without violating operating constraints. This problem has many constraints and it is very difficult to find the optimal solution because of its numerous local minima. In this investigation, a parallel AEA was developed for the service restoration of the distribution systems. In parallel AEA, a genetic algorithm (GA) and an evolution strategy (ES) in an adaptive manner are used in order to combine the merits of two different evolutionary algorithms: the global search capability of the GA and the local search capability of the ES. In the reproduction procedure, proportions of the population by GA and ES are adaptively modulated according to the fitness. After AEA operations, the best solutions of AEA processors are transferred to the neighboring processors. For parallel computing, a PC cluster system consisting of 8 PCs was developed. Each PC employs the 2 GHz Pentium IV CPU and is connected with others through switch based fast Ethernet. To show the validity of the proposed method, the developed algorithm has been tested with a practical distribution system in Korea. From the simulation results, the proposed method found the optimal service restoration strategy. The obtained results were the same as that of the explicit exhaustive search method. Also, it is found that the proposed algorithm is efficient and robust for service restoration of distribution systems in terms of solution quality, speedup, efficiency, and computation time.

• 한국콘텐츠학회논문지
• /
• 제22권4호
• /
• pp.182-189
• /
• 2022

전 세계적으로 OTT 서비스가 대중화됨에 따라 새로운 콘텐츠가 끊임없이 유통되는 플랫폼 미디어 산업 생태계에서 콘텐츠 IP 확장 전략은 콘텐츠 제작방식에 있어 중요한 위치를 갖는다. 그 중에서도 특정한 세계를 구성하는 구성요소, 즉 세계관을 확장하는 방식은 콘텐츠 IP 전략에서 위험요소를 줄이고 콘텐츠 프랜차이즈를 구축하는데 있어 효과적이다. 본 연구는 마블의 영화적 세계관(MCU)이 어떻게 멀티버스 개념을 차용하여 자기 스스로 이를 복제하고 재생산하면서 콘텐츠 IP 확장을 전략적으로 수행하고 있는지 <로키(Loki)>의 서사 분석을 통해 살펴보고자 한다. 결과적으로 멀티버스 세계관은 완결된 사건을 반복하여 비/완결 상태를 재생산 할 수 있고, 이는 완결된 또 다른 자기충족적 콘텐츠로 존재가능하다. 동시에 멀티버스 세계관 아래 하나의 캐릭터가 다수로 존재 가능하기 때문에 복수의 이야기를 생산해낼 수 있다는 점에서 효과적인 콘텐츠 IP 확장전략이 될 수 있다.