• Journal of KIISE
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• v.42 no.8
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• pp.972-978
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• 2015

Non-volatile memory (NVM) supports both byte addressability and non-volatility. These characteristics make it feasible for NVM to be employed at any layer of the memory hierarchy such as cache, memory and disk. An interesting characteristic of NVM is that, even though it supports non-volatility, its retention capability is limited. Furthermore NVM has tradeoff between its retention capability and write latency. In this paper, we propose a novel NVM-based file cache management scheme that makes use of the limited retention capability to improve the cache performance. Experimental results with real-workloads show that our scheme can reduce access latency by up to 31% (24.4% average) compared with the conventional LRU based cache management scheme.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.232-234
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• 1996

The self-refresh mode was introduced as method to reduce power dissipation in DRAM. Because the data retention time of DRAM cell decreases as the ambient temperature rises, the internal period in self-refresh mode must be limited by retention capability at the highest temperature in DRAM specification. Because of this, at room temperature($25^{\circ}C$) unnecessary power dissipation happens, If the period of self-refresh could be modulated as temperature, it is possible to reduce the self-refresh current. In this paper, new temperature detector circuit is suggested as this purpose.

• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.617-648
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• 2009

Under the government supported long-term nuclear R&D program, the severe accident research program at KAERI is directed to investigate unresolved severe accident issues such as core debris coolability, steam explosions, and hydrogen combustion both experimentally and numerically. Extensive studies have been performed to evaluate the in-vessel retention of core debris through external reactor vessel cooling concept for APR1400 as a severe accident management strategy. Additionally, an improvement of the insulator design outside the vessel was investigated. To address steam explosions, a series of experiments using a prototypic material was performed in the TROI facility. Major parameters such as material composition and void fraction as well as the relevant physics affecting the energetics of steam explosions were investigated. For hydrogen control in Korean nuclear power plants, evaluation of the hydrogen concentration and the possibility of deflagration-to-detonation transition occurrence in the containment using three-dimensional analysis code, GASFLOW, were performed. Finally, the integrated severe accident analysis code, MIDAS, has been developed for domestication based on MELCOR. The data transfer scheme using pointers was restructured with the modules and the derived-type direct variables using FORTRAN90. New models were implemented to extend the capability of MIDAS.

• Journal of Engineering Education Research
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• v.26 no.6
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• pp.3-18
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• 2023

The purpose of this study is to identify the difference between the current retention level and the required level of engineering students' career competency that they think they need based on their perceptions. Ultimately, the results of this study are used as basic data when designing the major/general education program and the curricular/extra-curricular career program. The task of this study is to identify the difference between the current retention level and the required level of engineering students' career competency. And based on this, it is to confirm the educational needs of engineering students for the career competency. For this purpose, literature research on career competency education in universities was reviewed in the theoretical background. Next, previous studies on career competency and sub-competence derived from career competency-related studies and detailed questions were analyzed. Based on this, an initial evaluation tool for career competency of engineering students was developed. Finally, through expert review, a career competency evaluation tool with a total of 43 items in 10 competency groups was developed. A career competency evaluation questionnaire was conducted for 197 engineering students who participated in the 2022 Engineering Education Festa, and as a result of the IPA analysis, 'global competency' was found to be the competency with the largest difference between importance and execution. Next, 'major job competency' and 'career development competency' appeared in order. Reflecting the results of this study, it is expected that mutually organic design of competency-based liberal arts curriculum and major curriculum that can cultivate global competency, major job competency, and career development capability will be carried out through learning activities and field practice.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.5
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• pp.635-642
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• 2011

Hydraulic efficiency was a vital component in evaluating the disinfection capability of clearwell. Current practice evaluates these system based on the tracer test only. In this paper, CFD(Computational Fluid Dynamics) was applied on the clearwell for alternating or supplementing the tracer test. The baffle factor derived from the CFD modeling closely matched the values obtained from full scale tracer testing. And, for suggesting proper numerical model in clearwell; the turbulence model, discretization scheme, convergence criteria were investigated through separate simulation runs. The model validation was conducted by comparing the simulated data with experimental data. In the turbulence model, the realizable ${\kappa}-{\varepsilon}$ model and the standard ${\kappa}-{\varepsilon}$ model were found to be more appropriate than RNG ${\kappa}-{\varepsilon}$ model. The residuals of convergence criteria should be used as not $10^{-3}$ but $10^{-4}$ or $10^{-5}$. In discretization scheme, the difference of simulated values in 1st, 2nd, 3rd upwind scheme was found to be insignificant. Moreover, the result of this study suggest that CFD modeling can be a reliable alternative to tracer testing for evaluating the hydraulic efficiency.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.355-359
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• 2010

A $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ cathode was modified by applying a $ZrF_x$ coating. The surface-modified cathodes were characterized by XRD, SEM, EDS, TEM techniques. XRD patterns of $ZrF_x$-coated $Li[Co_{1/3}Ni_{1/3}Mn_{1/3}]O_2$ revealed that the coating did not affect the crystal structure of the parent powder. SEM and TEM images showed that $ZrF_x$ nano-particles were formed as a coating layer, and EDS data confirmed that $ZrF_x$ distributed uniformly on the surface the powder. Capacity retention of coated samples at high C rates was superior to that of pristine sample. However, as the coating concentration increases beyond the optimum concentration, the rate capability was deteriorated. Whereas, as the increase of coating concentration to 2.0 wt %, the cyclic performances of the electrodes under the severe conditions (high cut-off voltage, 4.8 V, and high measurement temperature, $55^{\circ}C$) were improved considerably.

• The Journal of Advanced Prosthodontics
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• v.7 no.3
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• pp.249-256
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• 2015

PURPOSE. The aim of this study was to evaluate the effects of atmospheric plasma (APL) versus conventional surface treatments on the adhesion of self-adhesive resin cement to Ti-6Al-4V alloy. MATERIALS AND METHODS. Sixty plates of machined titanium (Ti) discs were divided into five groups (n=12): 1) Untreated (CNT); 2) Sandblasted (SAB); 3) Tribochemically treated (ROC); 4) Tungsten CarbideBur (TCB); 5) APL treated (APL). SEM analysis and surface roughness (Ra) measurements were performed. Self-adhesive resin cement was bonded to the Ti surfaces and shear bond strength (SBS) tests, Ra and failure mode examinations were carried out. Data were analyzed by one-way analysis of variance and chi-squared test. RESULTS. The lowest SBS value was obtained with CNT and was significantly different from all other groups except for APL. The ROC showed the highest SBS and Ra values of all the groups. CONCLUSION. It was concluded that the effect of APL on SBS and Ra was not sufficient and it may not be a potential for promoting adhesion to titanium.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.1
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• pp.45-51
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• 2004

We have proposed a new shallow trench isolation (STI) process using flowable oxide (F-oxide) chemical vapor deposition (CVD) for DRAM application and it was successfully developed. The combination of F-oxide CVD and HDP CVD is thought to be the superior STI gap-filling process for next generation DRAM fabrication because F-oxide not only improves STI gap-filling capability, but also the reduced local stress by F-oxide in narrow trenches leads to decrease in junction leakage and gate induced drain leakage (GIDL) current. Finally, this process increased data retention time of DRAM compared to HDP STI. However, a serious failure occurred by symphonizing its structural dependency of deposited thickness with poor resistance against HF chemicals. It could be suppressed by reducing the flow time during F-oxide deposition. It was investigated collectively in terms of device yield. In conclusion, the combination of F-oxide and HDP oxide is the very promising technology for STI gap filling process of sub-100nm DRAM technology.

• The Journal of Industrial Distribution & Business
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• v.14 no.11
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• pp.19-25
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• 2023

Purpose: Prior studies regarding ethical management on worker's performance have primarily focused on specific industries or regions, potentially limiting the generalizability. This gap in knowledge underscores the need for a comprehensive investigation that considers a diverse range of industries and thoroughly examines the multifaceted aspects of ethical management. Research design, data and methodology: The academic search platform used for this study was 'Google Scholar', 'Scopus', and 'Web of Science' indexes various scholarly articles, including peer-reviewed journals and books. By utilizing specific search terms such as "corporate ethical management" and "employee performance," a vast pool of relevant studies was identified. Results: The findings indicated four effects: first, a positive correlation between ethical management practices and heightened employee motivation and engagement; second, an augmentation in organizational commitment and job satisfaction among employees; third, a reduction in turnover rates, indicating enhanced employee retention; and fourth, an elevation in overall productivity and performance outcomes. Conclusions: In sum, this study offers actionable insights, advocating for adopting and reinforcing ethical management strategies as a potent means to foster a high-performance work culture. These encompass fostering a robust ethical framework, cultivating a culture of transparency and open communication, and providing avenues for employees to voice ethical concerns without fear of retribution.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.3185-3199
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• 2018

Middle- and old-aged driver's capability in recognition for driving scene elements was compared. Central and ambient stimuli were selected from natural driving scene and sensitivity, bias and reaction time were measured as dependent measures. The results are as follows. First, in general, older drivers showed lower sensitivity than middle-aged drivers. In particular, the older drivers' sensitivity was significantly lower for the ambient stimuli than central stimuli, whereas the middle-aged drivers showed no significant difference between the two types of stimuli. Second, the older drivers tended to show more lenient responses whereas the middle-aged drivers responded more conservatively. Third, the older drivers showed longer reaction time than the middle-aged drivers, in particular, in the responses of miss and correct rejection. This results suggested that the older drivers' retention for driving scene elements in their working memory may not be stable, which can be resulted in difficulties in rapid and accurate responses in a real life driving.