• The Journal of the Korea Contents Association
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• v.21 no.7
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• pp.558-566
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• 2021

This study was conducted to classify college students using games based on the stress, satisfaction and balance of basic psychological needs and to identify how gaming behaviors differ according to the divided clusters. This study used data of 447 college students who used games with the support of JangHoon Scholarship Foundation. As a result, the college students using games were divided into four groups with different characteristics according to stress, satisfaction and balance of basic psychological needs. Also, the level of gaming behavior was different according to the degree of satisfaction of basic psychological needs. The lower the stress and the higher the balance when the level of satisfaction was similar, the lower the level of gaming behaviors was. This study confirmed the importance of satisfactory balance of basic psychological needs as well as satisfaction, and supported the biopsychological perspective by suggesting that there are significant differences in gaming behavior according to clusters.

• Journal of the Korea Convergence Society
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• v.13 no.5
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• pp.483-488
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• 2022

This study was conducted to compare of dietary behaviors of young and temporary workers with older and permanent workers of single-person households. A questionnaire survey was conducted by purposive quota sampling(n=566) by age groups(20~59 years old) and status of workers(temporary workers, permanent workers and business owners). Compared to other age groups, 20s had lower average monthly income and cost of eating-out, and they rarely cooked at home and mainly bought food and groceries at convenience stores(p<0.001). This pattern was similar to temporary workers compare to other groups. This study will be meaningful as a basic data for creating a healthy living environment for temporary workers and 20s of single-person households.

• Journal of Information Processing Systems
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• v.18 no.6
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• pp.729-740
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• 2022

Netflix, Amazon Prime, and YouTube are the most popular and fastest-growing streaming services globally. It is a matter of great interest for the streaming service providers to preview their service infrastructure and streaming strategy in order to provide new streaming services. Hence, the first part of the paper presents a detailed survey of the Content Distribution Network (CDN) and cloud infrastructure of these service providers. To understand the streaming strategy of these service providers, the second part of the paper deduces a common quality-of-service (QoS) model based on rebuffering time, bitrate, progressive download ratio, and standard deviation of the On-Off cycle. This model is then used to analyze and compare the streaming behaviors of these services. This study concluded that the streaming behaviors of all these services are similar as they all use Dynamic Adaptive Streaming over HTTP (DASH) on top of TCP. However, the amount of data that they download in the buffering state and steady-state vary, resulting in different progressive download ratios, rebuffering levels, and bitrates. The characteristics of their On-Off cycle are also different resulting in different QoS. Hence a thorough adaptive bit rate (ABR) analysis is presented in this paper. The streaming behaviors of these services are tested on different access network bandwidths, ranging from 75 kbps to 30 Mbps. The survey results indicate that Netflix QoS and streaming behavior are significantly consistent followed by Amazon Prime and YouTube. Our approach can be used to compare and contrast the streaming services' strategies and finetune their ABR and flow control mechanisms.

• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.143-147
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• 1999

The present paper describes the solvent extraction behaviors and the mutual separation of Am and Eu by sulphur bearing Cyanex 301 acidic extractant in sodium nitrate solutions. Original Cyanex 301 was not able to separate the Am and Eu because of their similar extraction behaviors. The saponification of commercial Cyanex 301 was performed by small amounts of 8 M NaOH solutions and saponified Cyanex 301 was able to separate of Am from Eu with high selectivity in sodium nitrate aqueous solution. The separation factors ($SF_{Am/Eu}$) were increased with saponified ratio of commercial Cyanex 301, pH of sodium nitrate solution and initial concentration of Eu. To obtain the homogeneous saponified Cyanex 301, heterogeneous saponified Cyanex 301 was treated with addition of octyl alcohol or filtration. The observed $SF_{Am/Eu}$ was 32.3 for the former and 930 for the latter. Finally, the stripping behaviors of Am and Eu were similar and stripping yields showed 96.1% for the 1 M $NaNO_3$(pH=1.3) and 99% for the mixture solution of 0.05 M DTPA and 1.5 M lactic acid.

• The Journal of the Korea Contents Association
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• v.12 no.3
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• pp.260-267
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• 2012

This study was survey about the oral health knowledge and behaviors with alternative school students results are as follow. 1. As a result of this study, toothbrushing period was the largest with 29.5% in students of doing 'after dinner.', The appearance of taking food of containing sugar for preventing caries was the largest with 53.3% in students who responded as saying of 'tending to be not so.', A path of acquiring information on oral health knowledge was the highest with 72.0% in neighbor and family. 2. A review of Toothbrushing frequency per day, this was the largest with 45.2% in execution with 3 times, There were difference depending on grade, sex, a path of go to school, come home from school, financial status. 3. A review of the oral hygiene auxiliary supplies, this was the largest with 64.5% in students who used it, There were difference depending on the higher school year in the high school, financial status. 4. as a result of taking snack of students, it was similar to two or three times with 37.7%, one time with 34.6% per day, there was difference depending on financial status. taking drink was similar to non-drink with 38.0%, one time with 37.7%, there were difference depending on grade, financial status in a statistics.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.91-100
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• 1996

Condensed ethyl silicate(CES) solutions were prepared from $SiCl_4$ and ethanol which is different in water content(2.5, 5.0 and 7.0wt.% ). To investigate the sol-gel transition behaviors of CES and PHT(partially hydrolyzed TEOS) solutions, the measurement of volume change, density, $SiO_2$ content, intrinsic viscosity and number average molecular weight were conducted with elapsed time. The polymer shapes of CES were discussed from the relation between the intrinsic viscosity[$\eta$] and the number average molecular weight($\bar{Mn}$). CES-3 prepared from ethanol containing 7.0wt.% $H_2O$ had different sol-gel transition behaviors from CES-1 (2.5wt.% $H_2O$) and CES-2(5.Owt.% $H_2O$), but similar behaviors to those of PHT which is used for controlling the hydrolysis rata of TEOS when composite ceramic materials were manufactured from silicon alkoxides. On the basis of Mark-Hawink relation, $[{\eta}]=K\bar{Mn}^{{\alpha}}$, the polymer shape of CES solutions were determined linear siloxane polymers because all solutions had ${\alpha}$ values in the range from 0.53 to 0.84. Especially, CES-3 showed to be a favorable raw materials for composite ceramics due to its similar properties to those of PHT.

• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.377-384
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• 2010

We perform a comparative study to investigate the properties of the new energetic chain extender (AzPD). A series of poly(glycidyl azide)/poly(tetramethylene oxide)-based energetic segmented polyurethane (GAP/PTMG ESPU) with different chain extender, which is 3-azidopropane-1,2-diol (AzPD), 1,4-butane diol (1,4-BD), or 1,5 pentane diol (1,5-PD), was synthesized by solution polymerization in dimethyl formamide (DMF) and their phase behaviors were investigated. The ESPUs were characterized with Fourier transform infrared-attenuated total reflection spectroscopy (ATR FT-IR), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The results of the ATR FT-IR analysis of the urethane carbonyl group region showed that the 'free' C=O fraction was higher in GAP/PTMG AzESPU (0.5) than GAP/PTMG BDESPU (0.44) and GAP/PTMG PDESPU (0.41) for 7 days samples after preparation and that it was similar in the range of 0.26~0.29 for three 60 days ESPU samples. DMA curves of the GAP/PTMG AzESPU for 7 days samples showed amorphous polymers, but GAP/PTMG BDESPU and GAP/PTMG PDESPU showed viscoelastic behaviors with rubbery plateau and the flow region. However, DMA curves of the GAP/PTMG AzESPU for 60 days samples showed viscoelastic behaviors with rubbery plateau and the flow region like GAP/PTMG PDESPU, but GAP/PTMG BDESPU did not show the flow region. From phase behaviors with ATR FT-IR, DSC and DMA analysis, GAP/PTMG AzESPU showed good phase-mixing between components. However, it represented viscoelastic behavior of TPE similar to GAP/PTMG PDESPM according to phase equilibrium progress with aging time.

• Development and Reproduction
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• v.13 no.2
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• pp.79-87
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• 2009

Due to its well-known function in parturition and milk ejection, oxytocin (OT) has been considered as a 'female neurohypophyseal hormone'. Recent studies, however, clearly indicate that OT has some local roles in male reproduction via both central and peripheral routes. In experimental rodents, OT is released within distinct brain regions in response to social stimuli, and the brain OT receptor (OTR) mediated actions were strongly involved in the regulation of a variety of male behaviors such as mating-associated behaviors. In particular, OT and/or OTR knockout mice provide important clues about the molecular regulatory mechanism of the socio-sexual behaviors. Several lines of evidence also show that OT is synthesized within rodents testis, epididymis and prostate, and the presence of OTRs in these organs. In rodent testes, OT might have a role in the modulation of steroidogenesis via stimulation of the conversion of testosterone (T) to dihydrotestosterone (DHT) by 5alpha-reductase. Similar effects of OT on this androgen conversion were observed in epididymis and prostate suggesting the OT's modulatory role, such as contractility induction, in these androgen-dependent organs. In this context, further investigations on the OT's role in male CNS and reproductive organs are likely to provide better understanding on the complex socio-sexual behaviors and a platform for development of therapeutics to treat some psychological and/or andrological problems.

• Korean Journal of Construction Engineering and Management
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• v.14 no.6
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• pp.49-60
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• 2013

Evacuation process has been considered as one of the most important elements to be managed in public facilities. Although the importance is highlighted through numerous literatures, disaster evacuation planning, particularly fire accidents, faces a number of human behavior related limitations for a similar application to different types of facilities/occupants. To overcome the obstacles including complexity in human behaviors, a number of simulation techniques with limited consideration on human behaviors are utilized to predict foreseeable problems in evacuation process. Therefore, this research aims to propose system dynamics models incorporating human behaviors considering different types of occupants under disaster evacuation events. Analysis on emergent human behaviors such as group forming and interactions under urgent situation are conducted based on the main stream theories in social science field. The results suggest the influences of human behavior factors including cooperative intention, information sharing, and mobility change to evacuation behavior. The implications are expected to provide safety consideration at planning/designing phase of buildings and help facility safety managers for evacuation planning with more realistic management approaches.

• Journal of the Korean Society for Heat Treatment
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• v.30 no.2
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• pp.53-60
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• 2017

The aim of this study is to examine a feasibility to substitute Ti for Ta in reduced activation ferritic/martensitic (RAFM) steel by comparing a Ti-added RAFM steel with a conventional Ta-added RAFM steel. The microstructures and mechanical properties of Ta-, and Ti-added RAFM steels were investigated and a relationship between microstructures and mechanical properties was considered based on quantitative analysis of precipitates in two RAFM steels. Ta-, and Ti-added RAFM steels were normalized at $1000{\sim}1040^{\circ}C$ for 30 min and tempered at $750^{\circ}C$ for 2 hr. Both RAFM steels had very similar microstructures, that is, typical tempered martensite with relatively coarse $M_{23}C_6$ carbides at boundaries of grain and lath, and fine MX precipitates inside laths. The MX precipitates were identified as TaC in Ta-added RAFM steel and TiC or (Ti, W)C in Ti-added RAFM steel, respectively. It is believed that these RAFM steels show similar tensile and Charpy impact properties due to similar microstructures. Precipitate hardening and brittle fracture strength calculated with quantitative analysis of precipitates elucidated well the similar behaviors on the tensile and Charpy impact properties of Ta-, and Ti-added RAFM steels.