목적 : 온도감응성 나노구조체를 제조하고 이를 적용하여, 보관시에는 항생제가 용출되지 않고, 안구착용시에 만 온도감응성으로 항생제를 용출하는 스마트 콘택트렌즈를 제조하고자 한다. 방법 : 에멀젼중합하여 p(NIPAAm)-기반의 나노구조체를 합성하였고, 이를 샌드위치 공법을 통해 콘택트렌즈 에 도입하였다. Soaking 방법을 통해 항생제인 levofloxacin(LVF)를 콘택트렌즈에 탑재하여 온도에 따라 항생제 용출 특성을 분석하였다. 결과 : sodium n-dodecyl sulfate (SDS) 마이셀 템플레이트를 활용한 에멀젼중합을 통해 20-40 nm 크기의 온도감응형 p(NIPAAm)-기반의 나노구조체를 합성하였고 이는 TEM과 입도분석기를 통해 확인하였다. 샌드위치 공법을 통해 콘택트렌즈에 나노구조체를 도입하였고, soaking 방법을 통해 항생제를 렌즈안의 나노구조체에 탑재 하였다. 25 oC와 35 oC에서 각각 항생제의 방출 특성을 분석하였다. 상온에서는 항생제를 3 ug 이내로 방출하였 지만, 35 oC에서는 2시간이내에 대부분의 항생제를 방출하였고 10 ug까지 방출하였다. 결론 : 본 연구에서는 온도감응형 나노구조체를 합성하고, 이를 콘택트렌즈에 적용 및 항생제를 탑재하여, 온 도감응형 스마트 항생제용출 콘택트렌즈를 제조하였다. 온도감응형 나노구조체는 콘택트렌즈안에서 항생제를 성 공적으로 탑재할 수 있었고, 상온에서 상당량의 항생체를 보관하고, 온도증가시 10 ug까지의 많은 양의 항생제를 방출하였다. 본 연구결과는 약물전달용 스마트 안과의료기기 및 콘택트렌즈의 개발 및 상용화에 큰 역할을 할 것 으로 기대된다.

목적 : 반응성 청색광차단 염료를 하이드로겔 콘택트렌즈에 화학적으로 고정시켰고, 제조된 콘택트렌즈의 청색 광차단 기능의 분석 및 첨가된 염료를 정량하고자 한다. 방법 : Vinyl sulfone-기반의 반응성 염료인 Reactive Orange 16 Dye를 다량의 알콜 작용기를 함유하는 하 이드로겔 콘택트렌즈에 화학적으로 결합시켰다. 콘택트렌즈의 청색광차단 특성 및 염료의 정량은 UV-vis spectrophotometer를 이용하여 확인하였다. 결과 : 청색광차단기능의 Reactive Orange 16 Dye가 성공적으로 하이드로겔 콘택트렌즈에 결합되었다. UV-vis spectra 분석을 통해 염료를 함유한 콘택트렌즈들이 우수한 청색광차단 기능을 보임을 확인하였다. Beer-Lambert의 법칙을 이용하여, 콘택트렌즈에 첨가된 Reactive Orange 16 Dye를 정량하였으며, 반응 염료 의 농도 조절을 통해, 콘택트렌즈의 청색광차단율을 조절할 수 있었다. 결론 : 본 연구에서는 청색광차단 기능의 반응성 염료를 하이드로겔 콘택트렌즈에 화학적 결합을 통해 고정시 키고, 청색광차단 기능을 분석하였다. 화학적 반응에서 청색광차단 염료의 농도가 증가할수록, 380~500 nm 사 이의 청색광 파장 영역에서의 차단 세기와 첨가된 염료의 양이 같이 증가함을 확인하였다. 대량생산이 가능한 청 색광차단 콘택트렌즈의 개발은 기능성 안광학의료기기 개발에 큰 역할을 할 것으로 기대된다.

Due to the issue of the sustainability in transportation area, the number of electric vehicles has significantly increased. Most automakers have decided or planned to manufacture the electric vehicles rather than carbon fueled vehicles. However, there are still some problems to figure out for the electric vehicles such as long charging time, driving ranges, supply of charging stations. Since the speed of growing the number of electric vehicles is faster than that of the number of charging stations, there are lack of supplies of charging stations for electric vehicles and imbalances of the location of the charging stations. Thus, the location problem of charging stations is one of important issues for the electric vehicles. Studies have conducted to find the optimal locations for the charging stations. Most studies have formulated the problem with deterministic or hierarchical models. In this paper, we have investigated the fluctuations of locations and the capacity of charging stations. We proposed a mathematical model for the location problem of charging stations with the vehicle routing problem. Numerical examples provide the strategy for the location routing problems of the electric vehicles.

Global concerns have grown regarding emerging infectious diseases (EIDs) caused by previously unknown pathogens. Considering that strengthening surveillance capacity for unknown diseases is one of the core capacities for preparedness and early response to EIDs, identifying areas with poor capacity could be beneficial to prioritize regions for the improvement of surveillance. In this regard, we aimed to develop prediction models to identify high risk areas for low surveillance capacity for unknown diseases in a global scale. Unexplained death events reported between 2015 and 2019 were collected from two internet-based surveillance systems, ProMED-mail and Global Public Health Intelligence Network. From the reports, the number of reported unexplained deaths at the first report and the time gap between death and report were extracted as measures for sensitivity and timeliness of surveillance capacity, respectively. Using geographical locations of the reports and published global scale spatial data, including demographic, socioeconomic, public health and geographical variables, we fitted two boosted regression tree models to predict regions with the low sensitivity and timeliness. The performance of prediction model for the low sensitivity showed moderate validity, but in terms of the model for timeliness, the performance was unreliable. Therefore, we provided predicted risk only for low sensitivity. The mean predicted risks of low sensitivity were, respectively, 45.2%, 37.4%, 12.5%, and 3.0% in low-income, lower middle-income, upper middle-income, and high-income countries. Enhancing surveillance capacity in low-income countries is highly required, given the predicted low level of sensitivity despite the importance of early response.

This paper addresses the maintenance optimization problem in multi-component systems in which parts are connected in series, carrying out several missions interspersed with scheduled finite breaks. Due to limited time or resources, maintenance actions can be only carried out on a limited set of components. The decision maker then has to decide which components to maintain to ensure a pre-specified performance level during next mission. Most of the existing models in the literature usually assume only one system and enough spare parts. However, there are situations in which maintenance is required for multiple systems of the same type. To overcome this restrictive assumption, this study optimizes the maintenance problem considering the lack of repair parts and cannibalism for many identical systems. This study presents two optimization models with different objectives to solve the problem and analyzes the results so that the decision maker can decide. The results of this study are expected to be used for the maintenance of multiple systems of the same type, such as swarm drones.

Agrophotovoltaic (APV) system is an integrated system producing crops as well as solar energy. Because crop production underneath Photovoltaic (PV) modules requires delicate management of crops, smart farming equipment such as real-time remote monitoring sensors (e.g., soil moisture sensors) and micro-climate monitoring sensors (e.g., thermometers and irradiance sensors) is installed in the APV system. This study aims at introducing a decision support system (DSS) for smart farming in an APV system. The proposed DSS is devised to provide a mobile application service, satellite image processing, real-time data monitoring, and performance estimation. Particularly, the real-time monitoring data is used as an input of the DSS system for performance estimation of an APV system in terms of production yields of crops and monetary benefit so that a data-driven function is implemented in the proposed system. The proposed DSS is validated with field data collected from an actual APV system at the Jeollanamdo Agricultural Research and Extension Services in South Korea. As a result, farmers and engineers enable to efficiently produce solar energy without causing harmful impact on regular crop production underneath PV modules. In addition, the proposed system will contribute to enhancement of the smart farming technology in the field of agriculture.

Investors must adopt profitable investment opportunities to maximize their wealth. Almost all investment, finance, engineering economics textbooks explain that net present value (NPV) measures the profitability (or value) of investment opportunities in absolute size, and internal rate of return (IRR) measures the profitability of investment opportunities in relative proportions. However, NPV is a measure of the relative size of the return on investment opportunity to do-nothing alternative. Moreover, IRR can occur in multiple investment opportunities and may not exist. To make matters worse, IRR and NPV also have conflicting problems in accept-or-reject decisions. In this study, the reason why NPV and IRR cannot accurately measure the profitability of investment opportunities is identified, and fundamental characteristics that investment opportunity profitability measures should have are presented.

In the case of a die-casting process, defects that are difficult to confirm by visual inspection, such as shrinkage bubbles, may occur due to an error in maintaining a vacuum state. Since these casting defects are discovered during post-processing operations such as heat treatment or finishing work, they cannot be taken in advance at the casting time, which can cause a large number of defects. In this study, we propose an approach that can predict the occurrence of casting defects by defect type using machine learning technology based on casting parameter data collected from equipment in the die casting process in real time. Die-casting parameter data can basically be collected through the casting equipment controller. In order to perform classification analysis for predicting defects by defect type, labeling of casting parameters must be performed. In this study, first, the defective data set is separated by performing the primary clustering based on the total defect rate obtained during the post-processing. Second, the secondary cluster analysis is performed using the defect rate by type for the separated defect data set, and the labeling task is performed by defect type using the cluster analysis result. Finally, a classification learning model is created by collecting the entire labeled data set, and a real-time monitoring system for defect prediction using LabView and Python was implemented. When a defect is predicted, notification is performed so that the operator can cope with it, such as displaying on the monitoring screen and alarm notification.

Transportation in urban area has been getting hard to fulfill the demand on time. There are various uncertainties and obstacles related with road conditions, traffic congestions, and accidents to interrupt the on-time deliveries. With this situation, the last mile logistics has been a keen issue for researchers and practitioners to find the best strategy of the problem. A way to resolve the problem is to use parcel lockers. Parcel locker is a storage that customers can pick up their products. Transportation vehicles deliver the products to parcel lockers instead of all customer sites. Using the parcel lockers, the total delivery costs can be reduced. However, the inconvenience of customer has to increase. Thus, we have to optimal solution to balance between the total delivery costs and customers' inconvenience. This paper formulates a mathematical model to find the optimal solution for the vehicle routing problem and the location problem of parcel lockers. Experimental results provide the viability to find optimal strategy for the routing problem as well as the location problem.

Iron deficiency is known to be a common nutritional disorder in many countries, especially among children, women of childbearing age and pregnant women. SUNACTIVE Fe-P80 is a new type of iron supplement that applies nanotechnlateology for the purpose of overcoming the disadvantages of food supplements. This study was conducted to investigate the potential adverse effects of a 28-day repeated oral dose of SUNACTIVE Fe-P80 in rats. SUNACTIVE Fe-P80 was administered once daily by gavage to Sprague-Dawley rats for 28 days at doses of 0, 500, 1,000, and 2,000 mg/kg/day. Additional recovery groups from the control and highdose groups were observed for a 14-day recovery period. At the scheduled termination, the animals were sacrificed, their organs weighed, and blood samples collected. There were no treatment-related effects in the context of clinical signs, body weight, food intake, ophthalmoscopy, urinalysis, necropsy findings, organ weights, and hematologic, serum biochemical and histopathological parameters at any dose tested. Under the present experimental conditions, the no-observed-adverse-effect level of SUNACTIVE Fe-P80 was ≥ 2,000 mg/kg/day in both the sexes, and no target organs were identified. Thus, the results suggest that SUNACTIVE Fe-P80 is relatively safe, as no treatment-related adverse effects were observed following a 28-day repeated oral dose experiment.

Over the past decade, platelet-rich plasma (PRP) and platelet derivatives have been widely investigated in the field of regenerative medicine due to their high concentrations of platelet- related growth factors, cytokines, and other proteins. Recently, many clinical studies have suggested their regenerative therapeutic efficacy in treating several disorders in medical field. However, their therapeutic applications are not well characterized in veterinary medicine as in human and experimental animals. This article reviews functional roles of platelets, scientific concepts, and clinical use of PRP and platelet derivatives in veterinary medicine. It also presents guidelines for veterinary applications of PRP in the future.

During the global health emergency, like the COVID-19 pandemic, people attend to organizations dedicated to international well-being. This paper aims to identify the construction of the World Health Organization’s (WHO) multiple identities attested in four identity processes: indexicality, local-occasioning, positioning, and dialogism. Identifying the organization’s identities can foster identity processes and help to understand the relationality of identities. Qualitative data from the WHO director-general’s media remarks on COVID-19 were collected and analyzed using a corpus analysis tool, AntConc. The tool allowed an investigation of word frequency, sentence structure patterns, and the use of keywords in sentences. This analysis revealed that the WHO has negotiated and presented several identities in COVID-19 situations. The results suggest that although factors such as audience and situations affect identity change, these negotiated identities are still coherent with the organization’s original identity.

Various non-face-to-face services are being activated due to the influence of the Corona 19 virus around the world. However, unlike the rapid development of delivery services, social awareness of delivery services is causing many problems. Therefore, in this study, we analyze the quality attributes of delivery services from the consumer's point of view, and based on the results, we try to derive a direction for service improvement. In this study, quality factors were established through interviews and surveys with actual consumers, and quality attributes were classified through the Kano model and Timko’s customer satisfaction coefficient. “Attractive” is (‘Ease of ordering, Accurate delivery to the designated place’), “One Dimensional” is (‘Variety of payment methods, Accurate delivery on time, Accurate delivery of ordered food, Degree of non-deformation of packaging conditions, etc., Convenience of use time’), “Must be” is (‘Kindness of the delivery person’), “Reverse” is (‘provision of services, service response to order discrepancies’). This study has academic significance in that it compensated for the disadvantage of not being able to interpret the mathematical meaning of the Kano model with Teamco’s customer satisfaction coefficient. It also has practical implications in that it provides an indirect clue to future improvement directions.

본 연구는 자살을 생각하는 학생들의 대학생활 적응, 심리상담 실태, 그리고 자살생각 영향요인을 파악 하고자 한다. 편의표집이나 특정전공자들을 대상으로 할 경우 자살생각 대학생들의 실태를 파악하기 어려 운 제한점이 있다. 따라서 비임상군인 재학생 전수를 대상으로 실시한 실태조사 결과를 분석함으로써 대학 생 자살생각의 심각성을 파악하고자 했다. 본 연구는 서울 소재 A대의 <학생실태 및 요구도 조사>(2021년 5~6월 실시, 재학생의 74.8%인 4,129명 응답)의 데이터를 사용하였다. 본 연구는 응답결과 중에서 기본정 보, 정신건강, 상담, 학교생활에 관한 내용을 중심으로 ‘자살을 생각한 집단’과 ‘자살을 생각하지 않은 집단’ 간의 차이를 비교하여 분석하였다. 자살을 생각한 집단은 혼자 거주하는 비율이 높고, 흡연량이 많고, 스마 트폰 사용 장애를 겪는 나타났다. 그리고 그들은 입학만족도, 전공만족도, 자아존중감 및 교우관계에 대한 만족도가 낮았고, 학업스트레스가 높은 것으로 나타났다. 또한 그들은 교내보다는 교외에서 심리상담을 받 은 비율이 높은 것으로 나타났다. 한편, 자살생각에 영향을 미치는 요인으로는 성별, 학년, 흡연량, 입학만족 도, 학업스트레스, 자아존중감, 심리상담 여부 등인 것으로 확인되었다. 이런 연구결과를 토대로 본 연구는, 심리상담에 대한 접근성을 제고할 수 있는 상담시스템의 구축과 자살위험군에 대한 체계적인 관리시스템의 구축을 제언하였다.

From a conversation-analytic perspective, this paper analyzes the “committal” suffixes ci and cianha used as “pseudo-tags” in Korean conversation, which render the utterance they mark a request for confirmation (RfC) formatted in the form of a polar declarative question. The focus is given to examining differences ci and cianha as constitutive of mutually related but distinct forms of RfC, particularly in terms of the ways in which the confirmable is formulated and intersubjective understanding is solicited and negotiated. It is proposed that the RfC formatted with the pseudo-tag ci indexes the speaker’s orientation towards having the recipient help him/her “raise commitment” to the factually ascertainable character of shared information. Its use organizes recipiency in such a way that the recipient’s confirmation is solicited collusively. The RfC formatted with cianha, by contrast, furnishes the speaker with a discursive resource for engaging the recipient in a negotiatory process, prodding him/her to raise his/her “momentarily latent” commitment. With the confirmable grounded in general/shared knowledge, the use of cianha has the import of organizing a range of “attendant activities”, such as appeasing, whining, rebuking, etc.

This study explored how task complexity, writing behaviors (i.e., pausing and revision behaviors), and writing performance (i.e., task completion, coherence and cohesion, language use, and expression and tone) influence and relate to each other. Thirty advanced-level Korean EFL undergraduates completed writing tasks differing in complexity. A combination of keystroke logging and stimulated recall interview was employed. It was found that the simple task group showed a greater number of pauses and revisions related to lower-order writing processes, whereas the complex task group showed longer pauses related to higher-order writing processes. While task complexity had no influence on writing performance, writing behaviors revealed significant relationships with text quality. In the simple task group, pause length and revision were negatively related to writing scores, whereas pause frequency revealed mixed results. In the complex task group, consistent negative relations were found between pausing behaviors and text quality, and fewer revisions were related to better scores in expression and tone.

2007년 메타버스 로드맵에서 메타버스 정의가 공식 발표된 바 있으며, 당시 국내외 연구자들에 의해 많은 논문이 발표되면서 학문적 이론적으로 정립하려는 노력을 해왔다. 이와는 달리, 산업계에서는 ‘메타버스’키 워드가 비대면 장기화와 맞물려 과열 양상을 보이고 있다. 정작 언급되는 메타버스 성공사례는 '게임'이거나 '게이미피케이션' 또는 ‘게임융합’ 사례가 다수다. 따라서, '메타버스'영역에도 게이미피케이션 이론과 원리의 적용은 바람직하다. 이에, 필자가 발표했던 DMGL 모델을 확장하여, 메타버스 내 습관형성 위한 다이내믹 모델을 제시하였다. 저자는 플레이어 경험을 향상시키기 위해 메타월드 습관 형성을 위한 4가자 양상의 모 델을 제안했다. P1) 플레이어는 세계관에 따라 전개되는 배경스토리를 따르며, 유발된 호기심으로 탐험할 동 기가 생성되고 게임의 조작법을 익히고 게임의 목표를 향하는 여정이다. P2) 플레이어는 메타월드의 조작법 익히기 단계로 온보딩 한다. P3) 플레이어는 아바타 꾸미기,아이템 획득/거래,커뮤니티 활동 등을 수행하면 서, 점차 목적(표)를 향한다. P4) 플레이어는 목적기능을 바로 수행할 수 있는 방식으로 온보딩한다. 이 모델 은 게임의 원리와 요소의 융합(게이미피케이션)으로, 후속연구에서 보다 심도 있는 연구 모델을 제시할 예 정이다.

디지털로 시작된 세대 간의 지식전복과 이에 따른 격차는 게임이라는 콘텐츠를 통해 그 차이점을 드러낼 것이라는 것을 가정하고 본 연구를 수행하였다. 이를 증명하기 위해 실제 부모의 게임에 관한 인식이 자녀 의 삶에 중요한 변수로 자리를 잡고 있는지 분석해 보는 것이 본 연구를 통해 알아보고자 하는 것이 주요 내용이었다. 분석 결과, 부모의 게임인식은 자녀의 삶에 직접적으로 영향을 미치진 않았다. 하지만 자녀가 판단했을 때 부모의 게임인식 수준은 자녀의 삶의 만족도에 상당한 영향을 미치고 있는 것으로 확인이 되 었다. 이는 부모가 스스로 판단하는 게임인식보다, 디지털 세대인 자녀의 게임 활동과 문화를 어떻게 인식 하고 대하는지에 따라 자녀의 행복에 영향을 미친다는 것이다. 본 연구의 결과는 자녀가 인식하는 부모의 게임인식과 자녀의 게임인식 간의 격차는 청소년 자녀의 행복에 매우 중요한 요인으로 작용을 하며, 이는 청소년 자녀의 게임 활동을 부모세대가 꼭 배우고 습득하는 것만이 자녀 세대를 이해하는 길이 아니라, 자 녀와 함께 소통하면서 현재의 상황을 이해하는 것이 보다 중요한 요인으로 나타났다고 할 수 있다. 시대적 상황에 의하여 한 가정 내에 부득이하게 발생한 문화적 취향의 차이지만, 이를 부모가 인정하고 이해하는 방향으로 소통을 진행한다면 자녀의 삶에 매우 긍정적인 영향을 줄 수 있다는 것을 의미하기도 한다.

PURPOSES : The aim of this study is to evaluate the stripping resistance of a bead coating via the Hamburg wheel tracking test and image analysis. METHODS : First, the stripping resistance of the bead coating was evaluated via the Hamburg wheel tracking test. A pneumatic wheel with a load of 175±2 N was used to simulate repeated skid cycles. Several bead coating mixtures with different numbers of coating layers, i.e., zero, one, two, three, and four layers, i.e., zero, one, two, three, and four layers,were conducted. Finally, an image analysis program was developed to analyze surface images captured from the Hamburg wheel tracking test. RESULTS : The results show that the samples with more coating layers exhibit higher stripping resistance. After 500 stripping cycles, the percentage of bead loss is 4% to 28%. At 80% bead loss, the mixture with one coating layer presents more skid cycles than the control sample without a coating layer. CONCLUSIONS : Incorporating a coating layer can improve the stripping resistance of glass beads under repeated skid cycles. Additionally, an image analysis program is established in this study to determine the percentage of bead loss caused by the stripping test.