Earticle

We consider a continuous-time individual’s optimal portfolio selection problem under the endogenous liquidity constraints. The economic agent faces limited commitment so the endogenous liquidity constraints are expressed as an outside option to stop participating in the financial market. We derive closed-form solutions for the optimal policies and verify that the endogenous liquidity constraints induce an endogenous wealth boundary of default. More quantitative results are provided in the case of constant relative risk aversion (CRRA) utility. The dual value function of the agent contains an outside option premium that leads to a lower consumption and a lower investment in the risky asset, in particular when the wealth level becomes closer to the default boundary.

We investigate the individual optimal consumption and investment problem under the timevarying liquidity constraint (TVLC), which is motivated by the U.S. data. When the agent has a constant relative risk aversion utility function, we provide the closed-form solution by a duality approach and characterize the optimal policies. The implications of the stochastic borrowing constraints for the optimal policies and implied wealth dynamics dier considerably from what has been shown in the previous literature on the xed borrowing limit such as the non-negative wealth constraint. We nd that the investment in the risky asset can be greater than the investment without any borrowing constraints due to the eect of the liquidity hedging demand. Remarkably, a risk-averse agent can rationally exhibit a locally risk-loving behavior when his/her wealth level approaches the borrowing limit. Moreover, as the income level increases, the impact of TVLC on the risky investment is not negligible, and in fact, becomes larger, even though the agent's credit limit under TVLC is higher for a higher level of income.

This paper presents methods of model predictive control (MPC) for eco-driving minimizing trip-time and energy- consumption of electric vehicles (EVs). Considering both non- convex and convex optimization problem formulations for MPC- based eco-driving, we compare the performances of nonlinear and linear MPC solutions for high-level planning of vehicle speed and charging in a driving simulation of a Munich– Cologne trip (573 km). The linear MPC can be considered as a convex quadratic programming approximation (i.e., convexified quadratic program) of the original nonlinear MPC, but its performance of optimality is shown to be comparable to the nonlinear counterparts whereas its computation speed is one order of magnitude faster.

Information cascade and overload have followed with the recent growth of online commerce platforms. Yet, increased spare time due to the isolated lifestyle during the COVID-19 pandemic has provided a unique opportunity for consumers to seek and consume online content with more cognitive effort than before. This study examines how the bias between perceived value and true value changes with a surge of search time created by the quarantine period. Using more than 3 million transaction data pertaining to the daily prices of about 7,800 soccer player cards of two entire seasons spanning the three years of 2018-2020 from the online FIFA, we find that expensive best-quality players become less popular during the pandemic period. In other words, the “superstar effects” seem to disappear when more search time becomes available for consumers. We also find that the prices of “second-best” players (i.e., players in the 3rd and 4th quintiles of the performance ranking) increase, implying that consumers substitute towards good-quality bargains from the top-notch players. Our findings suggest that when consumers have more search time, they gauge the true quality of products more carefully and purchase good-quality bargains such as the “second-best” players. We contribute to the literature by considering circumstance factors in search costs, such as time-oriented dimensions, rather than technical perspectives, and by highlighting the pivotal role of search time in terms of finding true value in the products.

This study compared types of time and money attitudes by respondents’ characteristics, and compared leisure consumption behavior and leisure satisfaction among different groups, which are classified by attitudes toward time and money. It also verified a structural model for the relationship of leisure satisfaction and the attitudes toward time and money, and investigated the moderating effects of leisure consumption behavior. Data were obtained from a questionnaire completed by 512 adult consumers. Using factor analyses and cluster analyses, this study classified the types of time and money attitudes. The time attitude was categorized according to four clusters: timeinsensibility, future- oriented, present-oriented, and past- oriented. The money attitude was divided into four clusters: future safety, stinginess/anxiety, diversion, and power/prestige. The major findings of this study were as follows: First, the propensity of leisure consumption behavior to seek fashion and conspicuousness was higher for time-insensibility group than for the others. However, the propensity of rational consumption behavior for leisure was higher for the future-oriented group. The level of leisure satisfaction was the highest for the time-insensibility group. Second, the propensity of leisure consumption behavior to seek fashion and conspicuousness was higher for those who considered money as tools for diversion and power/prestige. The propensity of rational consumption behavior for leisure was higher for the future safety and stinginess/anxiety groups. The level of leisure satisfaction was significantly higher for the diversion group. Third, from the results of structural analyses, the time-insensibility attitude showed a positive effect on the leisure consumption behavior to seek fashion and conspicuousness. The future-oriented attitude had a positive effect on the propensity of rational consumption behavior for leisure. The money attitudes of diversion and power/prestige had positive impacts on the leisure consumption behavior to seek fashion and conspicuousness, although they had negative effects on the propensity of rational consumption behavior for leisure. The leisure consumption behavior to seek fashion and conspicuousness had a positive effect on leisure satisfaction, although the rational consumption behavior for leisure had a negative effect.

Factor in global warming, environmental pollution, such as fear of black out, interest in energy-saving and low-carbon green growth is rapidly increasing worldwide. In developed countries, including Europe, the U.S., and has implemented daylight saving time as one of the measures for energy saving. The daylight saving time, by the time one hasten the standard time in the summer months to slow the sun floating immediately, you have carried out over 1948-60, 1987-88 twice in Japan. Implementation is carried out in the country of ice other than unnecessary to Midnight Sun and South Korea and Japan in Economic Co-operation and Development (OECD) in 30 countries, daylight savings time, including (27 countries), the United States, Canada ㆍ Brazil ㆍ Australia EU is being conducted in 86 countries around the world. Therefore, in this study, if you want to apply the daylight saving time, to analyze the effect on the energy consumption of buildings, to explore the architecture energy saving measures.

한국 내 학력인 인구의 감소에 따라 유학생 유치가 활발하게 이루어지고 있는 가운데 유학생의 중도 탈락률, 불법체류 등 유학생 관리 차원의 중요성이 드러나고 있다. 선행연구에 따르면 유학생의 성취동기와 시간관리 가치관은 교육소비 만족도에 영향을 미친다. 단, 성취동기와 시간관리 가치관 및 교육소비 만족도 간의 영향 관계를 명확히 규명한 연구는 부족하다는 것이 실정이다. 따라서 본 연구에서는 성취동기와 시간관리 가치와 중요성을 파악하고 양자와 교육소비 만족도 간의 영향 관계를 규명하는 것을 목적으로 한국 내 대학에 재학하고 있는 중국 유학생을 대상으로 설문조사를 진행하여 SPSS 26.0 통계프로그램을 사용하여 실증분석을 하였다. 연구 결과 성취동기는 시간관리 가치관에 유의한 정(+)의 영향을, 시간관리 가치관은 교육소비 만족도에 유의한 정(+)의 영향을 미치며, 시간관리 가치관은 성취동기와 교육소비 만족도 간의 관계에서 부분적 매개효과를 가진다는 것이 밝혀졌다. 마지막으로 본 연구 결과를 바탕으로 실무적 시사점, 한계점 및 향후의 연구 방향을 제시하였다.

This study is to verify the mediating effect of Time Management Values in the relationship between elements of the Achievement motivation and Education Consumption Satisfaction. To verify this, a survey was conducted on Chinese international students enrolled in Korean universities and empirical analysis was conducted using the SPSS 26.0 statistical program and research results are as follows. First, two elements of Achievement motivation have a significant effect on Time Management Values, and Time Management Values also have a significant effect on Education Consumption Satisfaction. Thus, it was found that Time Management Values played a mediating role in the relationship between the two elements of Achievement motivation and Education Consumption Satisfaction. Based on these findings Practical Implications and future research directions were presented.

본 연구는 고령 인구를 단일‧동질 집단으로 간주해 온 기존 논의에서 벗어나, 한국 사회에 ‘액티브 시니어(active senior)’가 실제로 형성되고 있는지를 실증적으로 검토 하였다. 이를 위해 2014년부터 2023년까지 10개 연도에 걸친 재정패널(Financial Panel) 자료와 언론수용자 패널 데이터를 병합하고, 25세부터 75세 이상까지 여섯 연령 집단(25–34, 35–44, 45–54, 55–64, 65–74, 75+)의 소득 구조(근로·사업소득 vs. 재산소 득), 소비 지출(여가, 통신) 및 뉴스 미디어 이용(포털·검색, SNS, 종이신문, TV)을 시계열로 비교‧분석하였다. 분석 결과, 55–64세와 65–74세 집단에서는 45–54세 집단과의 여가·통신 지출 격차와 포털‧검색 및 TV 뉴스 이용 격차가 통계적으로 유의하게 축소 되었으며, 반대로 재산소득 격차는 확대되는 경향을 보였다. 이는 경제적 능력과 디지 털 역량을 동시에 보유한 ‘액티브 시니어’의 부상 가능성을 시사한다. 75세 이상 집단에 서도 유사한 변화가 관측되었으나, 그 폭은 상대적으로 제한적이었다. 특히 액티브 시 니어 특성이 가장 뚜렷한 55–64세 집단을 대상으로 한 추가 상관분석에서는, 여가·통 신 지출 격차 축소가 종이신문·포털·TV 뉴스 이용 격차 축소와 높은 정(+)적 상관관 계를 나타내어, 소득 변화보다 소비 행태와 미디어 이용 행태의 수렴이 더욱 급진적으 로 진행되고 있음을 확인하였다. 이러한 결과는 고령층 내부에서도 세대 간 이질성이 확산되고 있음을 보여주며, 경제·문화·디지털 역량을 종합적으로 고려한 세분화된 정 책 설계와 산업 전략이 필요함을 시사한다. 나아가 본 연구는 장기 시계열 데이터를 통 해 고령자 집단의 행태 변화를 구체적으로 입증함으로써, 고령층 커뮤니케이션 연구의 범주 확장과 이론적 정교화에도 기여한다는 의의를 갖는다.

This study examines whether so-called “active seniors” are truly emerging in rapidly aging South Korea, positing that older adults do not constitute a homogeneous group. To this end, financial panel data and media usage panel data from 2014 to 2023 were combined to compare and analyze six age cohorts—ranging from 25 to 75 and above—across income (earned/business vs. asset), consumption expenditures (leisure, communication), and news media use (portal/search, SNS, print newspapers, TV). Findings show that adults aged 55 to 74 exhibit significant convergence with the middle-aged reference group (45-54) in leisure and communication spending, as well as portal and TV news usage, while their asset-income gap widens. Although a similar trend is observed among those 75 and older, the magnitude of change is relatively limited. Notably, a correlation analysis focusing on the 55–64 cohort— where active-senior characteristics appear most prominent—reveals a strong positive relationship between narrowing gaps in leisure/communication spending and reduced disparities in both traditional and digital news usage. These results suggest that shifts in consumption and media behavior are more salient than changes in income. By adopting a time-series perspective, this study illuminates the evolving economic, cultural, and digital practices of older adults and underscores the need for segmented strategies that cater to the diverse needs of this growing population.

A method had been constructed for mobile cloud computation offloading switch based on decision value model. In this method, two important ratios had been built: one is the calculation ratio which are offloaded on a proxy server completed tasks time and at the mobile node completed tasks time. Another is the calculation ratio which is offloaded on proxy server completed tasks energy and at the mobile node completed tasks energy. And then, decision value function was produced by combining with these two ratios. Finally, consider the optimization switch problem of computing tasks between different proxy servers. Experimental results show that the proposed method has a smaller time consumption and energy consumption by comparing with random offloading switch and minimum time-based offloading switch, and battery remaining of mobile node can be used rationally.

With the single chip microcomputer as the core, a kind of multi-function detection system of vehicle fuel oil is designed by using sensor and signal processing circuit. Signal can be converted into electrical signal and connected to A/D converter through the oil signal acquisition channel, instantaneous oil signal acquisition channel, respectively. In the system, output data is displayed through the software programming and the corresponding circuits. The tests show that the system can automatically and accurately monitor all cases of the fuel oil and it is very important for the drivers to know the conditions of the vehicle fuel oil.

Wireless body area network (WBAN) is a communication standard optimized for low power devices and operation on, in or around the human body but not limited to humans used to serve a variety of applications including medical, consumer electronics, entertainment and other[1]. The challenge of WBAN is that the energy of the sensors is limited by the battery life that’s why the transmitting of data is not continuous for long time. This leads to poor efficiency of the WBAN because the continuous power decreasing is due to network operations. An algorithms such as MAC zigbee802.15.4 and adaptive reliable MAC are important to reduce the replacement of batteries many times and to save power consumption. In this paper we concentrated our study on some type of sensors, they are telosB, mica2, micaz, and imote2 depends on power consumption calculations using mat lab program and based on adaptive reliable MAC. We analyzed the sensors with several nodes and packet sizes, and calculate the lifetimes for all the sensors in WBAN. The results we obtained show a good performance of using Adaptive reliable MAC in Wireless Body Area Networks.

When looking for a way to develop a program with artificial intelligent, the most common related concept is the artificial neural network (ANN). Due to being a computational model of a biological neural network that can be used for simulating, processing or prediction. This article have as objective the mathematical implementation of a feedforward neural network in C# programming language. To achieve the previous, the behavior of a MATLAB ® neural network was analyzed, with the purpose of making the data adjustment that allows identify the energy consumption for a building from weather and time variables.

Based on economic growth theory of modern economic theory, with Fujian Province as object of study, panel data from 1981 to 2013 is selected in this paper. Besides, VAR model is established. Co-integration test, Granger causality and impulse response function are used for quantitative analysis on correlation between consumption, investment, import, export and economic growth in Fujian Province. With Eviews8 software as analytical tool, the empirical study conducts analysis from the perspective of econometrics and tests the stationarity of unit root data; determines optimal lag intervals through VAR model analysis on different lag intervals; determines the existence of co-integration relationship of data through Johansen co-integration test; tests the causality of data with Granger causality test; conducts stationarity test by establishing VAR model; studies the variation trend of influence of consumption, investment and import and export on economic growth in the next ten years through impulse response. The author reveals long-term stable balance among consumption, investment, import, export and economic growth in Fujian Province as well as bidirectional causal relationship between consumption and economic growth. For a short term, household consumption is of relatively strong positive impact effect on economic gain, which is served as major impetus of economic growth. Domestic investment is of relatively obvious promotion for economic growth in a short term and of certain negative effect on economic growth in a long term. Import and export have significant function for promoting economic growth and profound influence in Fujian as coastal city. On this basis, the author proposes some policies and recommendations for macroeconomic regulation and control in Fujian Province.

본 연구는 경제적 여유와 여가시간이 증대되어 여가에 대한 중요도가 높아지면서 여가 지출도 과거와 달리 소비지출의 중요한 요소로 부각되고 있다. 그 간 여가소비지출에 대한 관광학 분야에서의 연구는 여가행위 및 여가심리 분야에 초점이 맞추어져, 경제성장이 예견되는 실정에 직접적인 영향을 미치지 못한 것으로 사료되기 때문에 거시경제변수가 여가소비지출에 어떤 영향을 미치는지에 대해 연구하고자 한다. 본 연구를 통해 변화하는 경제 속에서 공공부문의 여가정책수립과 민간부문의 여가산업의 발전방향을 제시하는데 유용한 시사점을 제공할 것으로 사료된다. 분석 결과, 여가소비지출에 영향을 미치는 거시경제변수는 상이하게 나타났다. 가구소득과 1인당 실질 GDP는 정(+)의 영향을 미치며, 물질적 풍요가 여가의 중요한 결정요소임을 나타내었다. 환율은 다소 낮은 부(-)의 영향을 나타내었으며, 선행연구와 상반되는 결과가 나타난 이유는, 국제여행과 여가소비에 대한 성격차이가 어느 정도있기 때문이라 판단된다. 실업률은 다소 낮은 정(+)의 설명력을 나타내었으며, 여가를 즐길 수 있는 시간적 여유가 늘어나기 때문에 소비가 증가한다는 것을 시사한다. 경제성장률은 정(+)의 영향을 미치며, 이는 여가소비가 경제성장에 영향을 받고 있고 향후 경제 성장과 더불어 여가소비도 증가할 것이라는 점을 시사 해 준다.

The economic affordability and leisure time is increased. The importance about the spare time is rising. And the spare time expense is standing out as the important factor of the consumption expenditure unlike a past. The tendency that I like this recognize the spare time as the important domain of the life was strengthened. It was recognized at the national view as the leisure industry as the key industries. The research in the field of the tourism for the spare time consumption expenditure is various. There was no study that I deal the macro-economic variables and spare time consumption expenditure together. I am trying to present the leisure Industry direction of development of the public sector and private sector. The results of regression analysis, macroeconomic variables affecting consumer spending leisure were different. Household income, except for the exchange rate, real per capita GDP, unemployment, and economic growth in the leisure consumption expenditure on the impact of the positive (+) that appeared, and the exchange rate of (a) of explanatory showed.

In this study, we analyzed consumers' choices of various broadcasting and telecommunication convergence services and time consumption for chosen services by using survey data. A multivariate probit model was used to model consumers' choices of various broadcasting and telecommunication convergence services, and an ordered probit model was used to model consumers' time consumption for chosen services. Factors affecting consumers' choices and time-consumption behavior were identified, and simulation results of market competition and substitution were obtained. Based on these results, it was found that for the time being, consumers are highly locked into existing broadcasting services and are likely to become more price-sensitive to the new broadcasting and telecommunication convergence services. Also, the ways in which individual characteristics affect choices and time consumption were found to be very diverse service by service.

Relay coordination in power system is a complex problem and so far, meta-heuristic algorithms and other methods as an alternative approach may not properly deal with large scale relay coordination due to their huge time consuming computation. In some cases the relay coordination could be unachievable. As the urgency for a proper approach is essential, in this paper an innovative and simple relay coordination method is introduced that is able to be applied on optimization algorithms for relay protection coordination. The objective function equation of operating time of relays are divided into two separate functions with less constraints. As the analytical results show here, this equivalent method has a remarkable speed with high accuracy to coordinate directional relays. Two distribution systems including directional overcurrent relays are studied in DigSILENT software and the collected data are examined in MATLAB. The relay settings of this method are compared with particle swarm optimization and genetic algorithm. The analytical results show the correctness of this mathematical and practical approach. This fast coordination method has a proper velocity of convergence with low iteration that can be used in large scale systems in practice and also to provide a feasible solution for protection coordination in smart grids as online or offline protection coordination.

Adopting Internet of Things (IoT)-based technologies in smart homes helps users analyze home appliances electricity consumption for better overall cost monitoring. The IoT application like smart home system (SHS) could suffer from large missing values gaps due to several factors such as security attacks, sensor faults, or connection errors. In this paper, a novel framework has been proposed to predict large gaps of missing values from the SHS home appliances electricity consumption time-series datasets. The framework follows a series of steps to detect, predict and reconstruct the input time-series datasets of missing values. A hybrid convolutional neural network-long short term memory (CNN-LSTM) neural network used to forecast large missing values gaps. A comparative experiment has been conducted to evaluate the performance of hybrid CNN-LSTM with its single variant CNN and LSTM in forecasting missing values. The experimental results indicate a performance superiority of the CNN-LSTM model over the single CNN and LSTM neural networks.

We investigate an optimal retirement time and consumption/investment policy of a wage earner who expects to find a better investment opportunity after retirement by being freed from other work and participating fully in the financial market. We obtain a closed form solution to the optimization problem by using a dynamic programming method under general time-separable von Neumann-Morgenstern utility. It is optimal for the wage earner to retire from work if and only if his wealth exceeds a certain critical level which is obtained from a free boundary value problem. The wage earner consumes less and takes more risk than he would without anticipation of a better investment opportunity.

This study uses the 1999-2009 Korean Time Use Survey to explore how mothers' employment affects parental time spent in activities that may relate to their children's weight. Specifically, it estimates two-part regression models to assess the effects of maternal employment upon the amount of time mothers spend in activities potentially related to their preschool children's eating and physical activity. The findings suggest that working mothers and those mothers who work longer hours allocate significantly less time in food preparation, eating with the child, and supervising the child's physical activity than mothers who are not employed and those who work fewer hours. The paper also finds that spouses of working mothers do not allocate more time to these activities to offset the reduction in mothers' time. Also, using local unemployment rates as instrumental variables, maternal employment is found to allow mothers to spend significantly more time on food preparation and family meals, although its effect on mothers' total childcare time is negative. Several aspects of Korean society may have made the relationship between maternal employment and childhood weight issues different from what was found in other countries.