• Title/Summary/Keyword: EVs

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Assessment of Risk Factors for Postoperative Delirium in Older Adults Who Underwent Spinal Surgery and Identifying Associated Biomarkers Using Exosomal Protein

  • Baek, Wonhee;Lee, JuHee;Jang, Yeonsoo;Kim, Jeongmin;Shin, Dong Ah;Park, Hyunki;Koo, Bon-Nyeo;Lee, Hyangkyu
    • Journal of Korean Academy of Nursing
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    • v.53 no.4
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    • pp.371-384
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    • 2023
  • Purpose: With an increase in the aging population, the number of patients with degenerative spinal diseases undergoing surgery has risen, as has the incidence of postoperative delirium. This study aimed to investigate the risk factors affecting postoperative delirium in older adults who had undergone spine surgery and to identify the associated biomarkers. Methods: This study is a prospective study. Data of 100 patients aged ≥ 70 years who underwent spinal surgery were analyzed. Demographic data, medical history, clinical characteristics, cognitive function, depression symptoms, functional status, frailty, and nutritional status were investigated to identify the risk factors for delirium. The Confusion Assessment Method, Delirium Rating Scale-R-98, and Nursing Delirium Scale were also used for diagnosing delirium. To discover the biomarkers, urine extracellular vesicles (EVs) were analyzed for tau, ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), neurofilament light, and glial fibrillary acidic protein using digital immunoassay technology. Results: Nine patients were excluded, and data obtained from the remaining 91 were analyzed. Among them, 18 (19.8%) developed delirium. Differences were observed between participants with and without delirium in the contexts of a history of mental disorder and use of benzodiazepines (p = .005 and p = .026, respectively). Tau and UCH-L1-concentrations of urine EVs-were comparatively higher in participants with severe delirium than that in participants without delirium (p = .002 and p = .001, respectively). Conclusion: These findings can assist clinicians in accurately identifying the risk factors before surgery, classifying high-risk patients, and predicting and detecting delirium in older patients. Moreover, urine EV analysis revealed that postoperative delirium following spinal surgery is most likely associated with brain damage.

An Experiment Study on Electric Vehicle Fire and Fire Response Procedures (전기차 화재 실험 및 대응방안에 관한 연구)

  • Ki-Hun Nam;Jun-Sik Lee
    • Journal of the Korean Society of Industry Convergence
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    • v.27 no.1
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    • pp.63-70
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    • 2024
  • Lithium-ion batteries (LIB) are widely used in various sectors, such as transportation (e.g., electric vehicles (EV)) and energy (e.g., energy storage facilities) due to their high energy density, broad operating temperature (-20 ℃ ~ 60 ℃), and high capacities. LIBs are powerful but fragile on external factors, including pressure, physical damage, overheating, and overcharging, that cause thermal runaway causing fires and explosions. During a LIB fire, a large amount of oxygen is generated from the decomposition of ionogenic materials. A water fire extinguisher that helps with cooling and suffocating must be essentially required at the same time. In fact, however, it is difficult to suppress LIB fires in the case of EVs because a LIB is installed with a battery pack housing that interrupts direct extinguishing by water. Thus, this study aims to investigate effective fire extinguishing measurements for LIB fires by using an EV. Relevant documents, including research articles and reports, were reviewed to identify effective ways of LIBs fire extinguishing. A real-scale fire experiment generating thermal runaway was carried out to figure out the combustion characteristics of EVs. This study revealed that the most effective fire extinguishing measurements for LIB fires are applying fire blankets and water tanks. However, there is still a lack of adequate regulation and guidelines for LIB fire extinguishment. Taking this into account, developing functional fire extinguishment measurements and available regulatory instruments is an urgent issue to secure the safety of firefighters and citizens.

Evaluation of Electrical Damage to Electric-vehicle Bearings under Actual Operating Conditions (실제 운전조건을 고려한 전기자동차 베어링의 전기적 손상 평가 )

  • Jungsoo Park;Jeongsik Kim;Seungpyo Lee
    • Tribology and Lubricants
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    • v.40 no.4
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    • pp.111-117
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    • 2024
  • Due to global CO2 emission reductions and fuel efficiency regulations, the trend toward transitioning from internal combustion engine vehicles to electric vehicles (EVs) has accelerated. Consequently, the problem of EV failures has become a focal point of active research. The parasitic capacitance generated during motor-shaft rotation induces voltage that deteriorates the raceway and ball surfaces of bearings, causing electrical damage in EVs. Despite numerous attempts to address this issue, most studies have been conducted under high viscosity lubricant and low load conditions. However, due to factors such as high-speed operation, rapid acceleration and deceleration, motor heating, and motor system-decelerator integration, current EV applications have shown diminished stability in lubrication films of motor bearings, thereby leveraging the investigation to address the risk of electrical damage. This study investigates the electrical damage to rolling bearing elements in EV motor drive systems. The experimental analysis focuses on the effects of electric currents and operational loads on bearing integrity. A test rig is designed to generate high-rate voltage specific to a motor system's parasitic capacitance, and bearing samples are exposed to these currents for specified durations. Component evaluation involves visual inspections and vibration measurements. In addition, a predictive model for electrical failure is developed based on accumulated data, which demonstrates the ability to predict the likelihood of electrical failure relative to the duration and intensity of current exposure. This in turn reduces uncertainties in practical applications regarding electrical erosion modes.

The Effect of Perceived Shopping Value Dimensions on Attitude toward Store, Emotional Response to Store Shopping, and Store Loyalty (지각된 쇼핑가치차원이 점포태도, 쇼핑과정에서의 정서적 경험, 점포충성도에 미치는 영향에 관한 연구)

  • Ahn Kwang Ho;Lee Ha Neol
    • Asia Marketing Journal
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    • v.12 no.4
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    • pp.137-164
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    • 2011
  • In the past, retailers secured customer loyalty by offering convenient locations, unique assortments of goods, better services than competitors, and good credit policy. All this has changed. Goods assortments among stores have become more alike as national-brand manufacturers place their goods in more and more retail stores. Service differentiation also has eroded. Many department stores have trimmed services, and many discount stores have increased theirs. Customers have become smarter shoppers. They don't pay more for identical brands, especially when service differences have diminished. In the face of increased competition from discount storess and specialty stores, department stores are waging a comeback war. Growth of intertype competition, competition between store-based and non-store-based retailing and growing investment in technology are changing the way consumers shop and retailers sell. Different types of stores-discount stores, catalog showrooms, department stores-all compete for the same consumers by carrying the same type of merchandise. The biggest winners are retailers that have helped shoppers to be economically cautious, simplified their increasingly busy and complicated lives, and provided an emotional connection. The growth of e-retailers has forced traditional brick-and-mortar retailers to respond. Basically brick-and-mortar retailers utilize their natural advantages, such as products that shoppers can actually see, touch, and test, real-life customer service, and no delivery lag time for small-sized purchases. They also provide a shopping experience as a strong differentiator. They are adopting practices as calling each shopper a "guest". The store atmosphere should match the basic motivations of the shopper. If target consumers are more likely to be in a task-oriented and functional mindset, then a simpler, more restrained in-store environment may be better. Consistent with this reasoning, some retailers of experiential products are creating in-store entertainment to attract customers who want fun and excitement. The retail experience must deliver value to turn a one-time visitor into a loyal customer. Retailers need a tool that measures the full range of components that define experience-based value. This study uses an experiential value scale(EVS) developed by Mathwick, Malhotra and Rigdon(2001) which reflects the benefits derived from perceptions of playfulness, aesthetics, customer "return on investment" and service excellence. EVS is useful to predict differences in shopping preferences and patronage behavior of customers. EVS consists of items measuring efficiency, economic value, visual appeal, entertainment value, service excellence, escapism, and intrinsic enjoyment, which are subscales of experiencial value. Efficiency, economic value, service excellence are linked to the utilitarian shopping value. And visual appeal, entertainment value, escapism and intrinsic enjoyment are linked to hedonic shopping value. It has been found that consumers value hedonic experiences activated from escapism and attractiveness of shopping environment as much as the product quality, price, and the convenient location. As a result, many department stores, discount stores, and other retailers are introducing differential marketing strategy based on emotional/hedonic values. Many researches suggest that consumers go shopping not only for buying products but also for various shopping experiences. In other words, they seek the practical, rational value as well as social, recreational values in the shopping process(Babin et al, 1994; Bloch et al, 1994). Retailers may enhance buyer's loyalty to store by providing excellent emotional/hedonic value such as the excitement from shopping, not just the practical value of buying good products efficiently. We investigate the effect of perceived shopping values on the emotional experience and store loyalty based on the EVS(Experiential Value Scales) developed by Holbrook(1994), Mathwick, Malhotra and Rigdon(2001). This study assumes that the relative effect of shopping value dimensions on the responses of shoppers will differ according to types of stores and analyzes the moderating effect of store type(department store VS. discount store) on the causal relationship between shopping value dimensions and store loyalty. Emprical results show that utilitarian values of shopping experience and hedonic value of shipping experience give the positive effect on the emotional response of consumers and store loyalty. We also found the moderating effect of store types. The effect of utilitarian shopping values on the attitude toward discount store is higher than the effect of utilitarian shopping values on the attitude toword department store. And the effect of hedonic shopping value on the emotional response to discount store is higher than on the emotional response to department store. The empirical results reflect on the recent trend that discount stores try to fulfill the hedonic needs of consumers as well as utilitarian needs(i.e, low price) that discount stores traditionally have focused on

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자바를 이용한 Extended Virtual Synchrony의 지원

  • 문남두;최혁재;유양우;박양수;이명준
    • Proceedings of the Korean Information Science Society Conference
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    • 1998.10a
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    • pp.409-411
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    • 1998
  • 자바는 분산환경에 적합하고 이식성이 높으며 코드 재사용이 용이하다는 장점을 가지고 있다. 이러한 이유로 다양한 분야에서 자바로 구현된 응용서비스를 제공하고 있다. 현제와 같은 정보중심사회에서 이러한 자바응용서비스는 서버의 실패(crash) 나 네트워크 분할(partition)과 같은 결함이 발생되더라도 투명하고, 안정적이며, 지속적인 서비스를 제공하는 것이 바람직하다. 이러한 요구사항은 이기종 분산환경에서 동일한 서비스를 제공하는 자바응용서비스를 그룹으로 동작하게 함으로써 해결될 수 있다. 본 논문에서는 자바응용서비스 그룹이 네트워크의 분할로 상호 통신할 수 없는 두 개이상의 구성요소로 분리되더라도 지속적인 서비스를 제공하고 네트워크가 복구(merge)되면 이전과 같이 하나의 그룹으로서 동작할 수 잇도록 그룹 구성원의 일관성을 유지하는 EVS ( Extended Virtual Synchrony)모델을 구현함으로써 자바응용서비스의 신뢰성과 고가용성(high availability)을 지원하고자 한다.

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Current Activities of the EV Quick Charging System to the Rail Power Grid (철도 전력망을 이용한 전기자동차 급속충전시스템 개발 현황)

  • You, Sung-Han;Lee, Tea-Hoon;Cho, Yong-Chan;Park, Lea-Hyuk
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.3111-3116
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    • 2011
  • Global warming is one of the hottest issues which should be solved for future generations. Technologies which prevent the increase of environmental warming are highlighted as the global average temperature increases. Electric vehicles (EVs) are considered to be one of the powerful solutions to reduce greenhouse gas emission. To spread the EV industry, a major premise is that a charging infrastructure is available anywhere the EV operates. In this paper, we will present the demonstration of ' EV quick charging system to the rail power grid' which are cooperated by LS CNS, Seoul Metro and Korea Railway Research Institute.

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An Overview: Current Control Technique for Propulsion Motor for EV (전기자동차 구동용 모터를 위한 전류 제어 기술)

  • Lee, Hee-Kwang;Nam, Kwang-Hee
    • The Transactions of the Korean Institute of Power Electronics
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    • v.21 no.5
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    • pp.388-395
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    • 2016
  • Electric vehicles (EV) and hybrid EVs (HEV) are designed and manufactured by GM, Toyota, Honda, and Hyundai motors. The propulsion system design process for EV requires integrating subsystem designs into an overall system model to maximize the performance of a given propulsion architecture. Therefore, high-power density and high-torque density are important attributes required for EV applications. To improve torque and power density, propulsion motors are designed for saturation during high-torque operation. The nonlinearity associated with core saturation is modeled by incorporating the cross-coupling inductances, which also behave nonlinearly. Furthermore, in EV environments, the battery is directly connected to the DC link, and the battery changes depending on the state of charge. It will be onerous if as many optimal current commands as different $V_{dc}$ were made. This paper presents the optimal current commands in the various operating condition and the current control technique in EV environments.

A Study on Development of the Integration Charging Monitoring System for PHEVs and EVs (PHEV/EV용 통합 충전 모니터링 시스템 개발에 관한 연구)

  • Kim, Byoung-Hoon;Lee, Back-Haeng;Shin, Dong-Hyun;Jeong, Jin-Beom;Song, Hyun-Sik;Kim, Sang-Dae;Kim, Hee-Jun;Yoo, Ji-Yoon
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1204-1205
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    • 2011
  • 본 논문에서는 PHEV와 EV의 보급 확대에 따른 충전을 통합적으로 모니터링 할 수 있는 시스템을 제안하고 통합 충전 관리 시스템(Main-system)과 포스트(Sub-system) 운용 프로세스에 관해 설명하고자 한다. 충전 시스템 구성 비용 절감 및 사용 효율을 높일 수 있는 통합형 충전 시스템 구성을 위해 각 시스템간 통신 방식, 송수신 정보, 충전 및 제어 그리고 차량과의 인터페이스 기술 등 다양한 기능 정의와 통합 충전 모니터링 시스템의 장치 운용 알고리즘에 대해 알아보고자 한다.

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Optimal Resonant Frequency Design of Series-Loaded Resonant DC-DC Converter for EV On-Board Charger (EV 탑재형 충전기용 부하직렬공진형 컨버터의 최적 공진주파수 설계)

  • Oh, Chang-Yeol;Kim, Jong-Soo;Lee, Byoung-Kuk
    • Proceedings of the KIPE Conference
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    • 2011.07a
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    • pp.167-168
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    • 2011
  • 본 논문에서는 전기자동차 (Electric Vehicles, EVs)에 사용되는 탑재형 충전기 (On-Board Charger, OBC)에 적용된 부하직렬공진형 컨버터 (Series-Loaded Resonant DC-DC Converter, SRC)의 최적 공진주파수를 설계하기 위한 과정을 제시한다. 실제 OBC제품의 입 출력을 토대로 프로세스를 진행하여, 다양한 주파수에 따른 공진 네트워크를 구성한다. 그 결과로 얻어진 파라미터를 이용하여 스위칭 주파수에 따른 자성소자의 사이즈 변화 및 손실량 변화 추이를 분석하여 최적의 설계점을 찾는다.

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The Role of Innovative Energy Public Firms' Channels according to Shale Gas for E-Convergence Economy.

  • Seo, Dae-Sung;Kim, Seung-Ryeol
    • Journal of Distribution Science
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    • v.14 no.5
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    • pp.17-26
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    • 2016
  • Purpose - The E-convergence economy is requested with the economic change of the diverse energy supplies, according to the exploits of Shale gas. By analyzing the electric energy supply and demand in accordance with the various cases, it has proved indirectly to create a convergence economy. Research design, data, and methodology - The research design would make realize its potential change with which government or companies have focused on the energy objection between Shale gas and Electric vehicles. Results - The paper suggests that Shale gas has expanded with the emphasis on the Electrical convergence economy or EVs. Due to these results, they also show why it should not be delayed in the development of shale gas and electric vehicles at the same time. Conclusions - All this is from the reason of opening the E-convergence economy over time. It is required that Korea should prepare E-convergence economy. Public regional energy should be present through the consistent selection of development for energy linking E-economy and E-trans distribution.