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We examine the argument of the Financial Supervisory Service that the behavior of the Individual Investors to buy an out-of-the-money option is excessively speculative. The FSS reported that the individual investors incurred huge losses in the trading of KOSPI200 index options for the years 2002 and 2003. But since the sample period is relatively short, the argument does not seem fully convincing. Using a longer period data from July 1997 to December 2003, we reconfirm the huge losses of the Individual investors and also find that a tendency of individual investors losing money in association with option trading perSisted during the longer period. The individual investors chose out-of-the money options with short time to maturity, that are cheap and thus are expected to make huge profits with very low probabilities. Finally, we tind that out-ot-the money options with short time to maturity turn out to be in general priced higher than what the Korea Stock Exchange model suggests.

The practice of purchasing out-of-the-money options for the reason of cheap prices and huge profit possibilities can be regarded as being excessively speculative. Due to overpricing, the individual investors persistently incurred some losses.

This paper investigates a retrospective on the Journal of Derivatives and Quantitative Studies (JDQS) on its 30th anniversary based on bibliometric. JDQSs yearly publications, citations, impact factors, and centrality indices grew up in early 2010s, and diminished in 2020. Keyword network analysis reveals the JDQS's main keywords including behavioral finance, implied volatility, information asymmetry, price discovery, KOSPI200 futures, volatility, and KOSPI200 options. Citations of JDQS articles are mainly driven by article age, demeaned age squared, conference, nonacademic authors and language. In comparison between number of views and downloads for JDQS articles, we find that recent changes in publisher and editorial and publishing policies have increased visibility of JDQS.

The objective of this paper is to understand changes and progress of the Korean childcare regime by examining the evolutional process of childcare initiatives that were developed since the Japanese colonial rule.

This study employed a qualitative-based research design with a particular emphasis on explanatory research. Meanwhile, the data were gathered through the peer-reviewed literature and reports.

The findings indicate that Korea has had three types of childcare regimes: effective-informal, productivist and inclusive-liberal orientation. It also pinpoints that while the care regime development followed the European regime, the egalitarian society, which is a social prerequisite for modern welfare state-building, has not yet been fully established. This paradoxical situation eventually impedes the development of universal childcare aimed at promoting gender equality and a work-life balance.

This article offers a model and characteristics of the Korean childcare regime dating back to the Japanese colonial period up until the Moon Jae-In administration, where it still receives less attention in most of the social policy literature (see Table 1).

Political analyses of the East Asian welfare state development often stress the importance of the power resource model, in which vibrant coalitions between the leftist party, interest groups, civil society and working-class unions have become driving factors in producing generous welfare outcomes. Challenging such analyses, this article discusses the convergence of the political attitude between political actors who are increasingly homogeneous (supportive) when it comes to the universal welfare state notion by focussing on childcare in South Korea.

By using desk review of the peer-reviewed literature and reports, this article investigates the causation for why political parties with different political ideologies were keen on extending childcare programs and its outcome in addressing the existing demographic problems in Korea.

Although the collective movement, especially in the 1990s and 2000s, had given important contributions to the early development of childcare in South Korea, more breakthroughs in childcare features were precisely and rapidly developed after politicians from different spectrums of political affiliations converged in their supportive attitude of the universal welfare. The driving factors of political convergence itself are not merely due to electoral competition or political activism; furthermore, it can be linked to the increased global institution involvement in domestic policy with extensive permeability, which, have ruined domestic policy development maintained for ideological reasoning and bring in more popular policy setting.

This article contributes to the growing literature on the political aspect of East Asian social policy studies, which goes beyond the traditional power resource analysis and makes a novel contribution to the childcare policy studies.

This work describes the fabrication of composite nanogrease based on carbon nanotubes (CNTs) as an additive at different volume concentrations 0, 0.5, 1, 2 and 3 Wt.% and investigates the correlation between CNTs and grease rheological behaviour. In addition, study the influence of shear thinning rate at various temperatures and investigates the thermal conductivity of nanogrease. The results demonstrated that grease behaves like a Newtonian viscoelastic material with a narrow linear domain. The thermal conductivity of nanogrease was enhanced by about 31.58 per cent, and the thermal and mechanical stabilities improved. Moreover, the apparent viscosity and dropping point increased by about 93 and 27 per cent, respectively.

Grease was dissolved in chloroform (10 Wt.%), at 25°C for 1 h. In parallel, functionalized CNTs with different volume concentrations (0.5, 1, 2 and 3 Wt.%) were dispersed in N,N-dimethylformamide; the dispersion was stirred for 15 min, and then sonicated (40 kHz, 150 W) for 30 min. Grease solution was then added to the CNTs. The nanofluid was magnetically stirred for 15 min and then sonicated for 2 h. This ensured uniform dispersion of nanoparticles in the base fluid.

Inexpensive and simple fabrication of nanogrease. Thermal conductivity of nanogrease was typically enhanced compared to other reported studies. Apparent viscosity and dropping point increases with the increase the volume concentration.

This work describes the inexpensive and simple fabrication of nanogrease for improving properties of lubricants, which improve power efficiency and extend lifetimes of mechanical equipment.

This paper aims to evaluate the effect of optimal use of rooftop photovoltaic (PV) systems on improving the loss of life (LOL) of distribution transformers, reducing power losses as well as the unbalance rate of the 69-bus distribution network.

The problem is studied in three scenarios, considering different objective functions as multi-objective optimization in balanced and unbalanced operations. Meta-heuristic golden ratio optimization method (GROM) is used to determine the optimal size of the rooftop PV in the network.

The simulation results show that in all scenarios, the GROM by optimally installing the rooftop PV is significantly capable to reduce the transformer distribution loss of loss, unbalance rate and power loss as well as reduce the temperature of the oil and transformer winding. Also, the lowest %LOL, power loss and unbalance rate occurred in the second scenario for the balanced network and first scenario, respectively. In addition, the results showed that the unbalance of the network results in increased power losses and LOL of the distribution transformer.

The better capability of GROM is proved compared with the grey wolf optimization algorithm with better objective function and by achieving better values of LOL, unbalance rate and power loss. The results also showed that the %LOL, unbalance and power losses are weakened compared to without considering the PV cost but the achieved results are realistic and cost-effective.