• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.5
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• pp.1019-1035
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• 2020

This study examines the millennial generation, who express themselves and share information on social media after experiencing constantly changing 'hot places' (places of interest) in contemporary cities, with the goal of analyzing space consumption behaviors. Data were collected via an Instagram crawler application developed with Python 3.4 administered to 19,262 posts using the term 'hot places' from November 1 and December 15, 2019. Issues were derived from a text mining technique using Textom 2.0; in addition, semantic network analysis using Ucinet6 and the NetDraw program were also conducted. The results are as follows. First, a frequency analysis of keywords for hot places indicated words frequently found in nouns were related to food, local names, SNS and timing. Words related to positive emotions felt in experience, and words related to behavior in hot places appeared in predicate. Based on importance, communication is the most important keyword and influenced all issues. Second, the results of visualization of semantic network analysis revealed four categories in the scope of the definition of "hot place": (1) culinary exploration, (2) atmosphere of cafés, (3) happy daily life of 'me' expressed in images, (4) emotional photos.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.557-561
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• 2004

The hot gas casing of gas turbine has operated high temperature and thermal gradient. The structure safety of hot gas casing will be highly depend on the thermal stress. In this paper, flow and thermal stress analysis of hot gas casing is carried out using ANSYS program. The obtained temperature data by flow analysis of hot gas casing apply the load condition of the thermal analysis. The thermal stress analysis is carry out the elastic-plasticity analysis. The pressure, temperature and velocity of the flow and thermal stress of the hot gas casing are presented.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.638-643
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• 2003

Channel width dependence of hot-carrier effect in nMOSFET with shallow trench isolation is analyzed. $I_{sub}$- $V_{G}$ and $\Delta$ $I_{ㅇ}$ measurement data show that MOSFETs with narrow channel-width are more susceptible to the hot-carrier degradation than MOSFETs with wide channel-width. By analysing $I_{sub}$/ $I_{D}$, linear $I_{D}$- $V_{G}$ characteristics, thicker oxide-thickness at the STI edge is identified as the reason for the channel-width dependent hot-carrier degradation. Using the charge-pumping method, $N_{it}$ generation due to the drain avalanche hot-carrier (DAHC) and channel hot-electron (CHE) stress are compared. are compared.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.05a
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• pp.163-168
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• 2002

Hot forging is widely used in the manufacturing of industry machine component. The mechanical, thermal load and thermal softening which are happened by the high temperature in hot forging process. Tool life decreases considerably due to the softening of the surface layer of a tool caused by a high thermal load and long contact time between the tool and billet. Also, tool life is to a large extent limited by wear, heat crack and plastic deformation in hot forging process. These are one of the main factors affecting die accuracy and tool life. That is because hot forging process has many factors influencing tool life, and there was not accurate in-process data. In this research, life prediction of hot forging tool by wear and plastic deformation analysis considering tempering parameter has been carried out for automobile component. The new developed technique in this study for predicting tool life can give more feasible means to improve the tool life in hot forging process.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.117-129
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• 2017

PURPOSES : The purpose of this study is to analyze the performance life of hot central plant recycling (HCPR) and hot in-place recycling (HIR) pavements applied to the National Highway for the past 20 years and compare it with conventional hot-mix asphalt (HMA) pavement. METHODS : In order to analyze the performance life of recycling asphalt pavements, a comprehensive literature review was conducted to investigate the government law and official system for the use of recycling asphalt pavement in Korea and foreign countries. Next, the application information of using a hot central plant recycling and hot in-place recycling pavements in the national highway is collected from the database of pavement management system (PMS) and then their field condition is visually surveyed. Finally, the performance life of recycling asphalt pavements in the national highway is analyzed and compared with conventional hot-mix asphalt pavement. RESULTS :Institutions are encouraging the promotion of using recycled asphalt pavement through various legal systems in Korea as well as abroad. Based on analysis results for the average performance life of hot central plant recycling pavement applied to the national highway, the average performance life is estimated to be 10.2 years. However, the average performance life of in-place recycling pavement is estimated to be 6.5 years. However, it is expected to increase performance life after the HIR construction system is modified. CONCLUSIONS : Based on the limited data analysis of the performance life of recycled asphalt pavements, HCPR shows similar performance life to conventional asphalt pavement but HIR shows shorter performance life than conventional asphalt pavement. However, it is noted that all performance life data is very limited and it should be monitored and analyzed further.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.336-340
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• 2010

Flash storages are prevalent as portable storage in computing systems. When we consider the detachability of Flash storage devices, data integrity becomes an important issue. To assure extreme data integrity, file systems synchronously write all file data to storage accompanying hot write references. In this study, we concentrate on the effect of hot write references on Flash storage, and we consider the effect of absorbing the hot write references via nonvolatile write cache on the performance of the FTL schemes in Flash storage. In 80 doing, we quantify the performance of typical FTL schemes for workloads that contain hot write references through a wide range of experiments on a real system environment. Through the results, we conclude that the impact of the underlying FTL schemes on the performance of Flash storage is dramatically reduced by absorbing the hot write references via nonvolatile write cache.

• Journal of KIISE
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• v.44 no.8
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• pp.782-790
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• 2017

The service, 'Hot Search Keywords', provides a list of the most hot search terms of different web services such as Naver or Daum. The service, bases the changes in rank of a specific search keyword on changes in its users' interest. This paper introduces a temporal modelling framework for predicting the rank change of hot search keywords using past rank data and machine learning. Past rank data shows that more than 70% of hot search keywords tend to disappear and reappear later. The authors processed missing rank value, using deletion, dummy variables, mean substitution, and expectation maximization. It is however crucial to calculate the optimal window size of the past rank data. We proposed an optimal window size selection approach based on the minimum amount of time a topic within the same or a differing context disappeared. The experiments were conducted with four different machine-learning techniques using the Naver, Daum, and Nate 'Hot Search Keywords' datasets, which were collected for 2 years.

• Transactions of Materials Processing
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• v.23 no.6
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• pp.357-362
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• 2014

The purpose of the current study is to predict the hardness distribution in steel products after hot stamping using a quench factor analysis(QFA) coupled with FE-simulations. QFA is a method to predict properties such as hardness and tensile strength based on time-temperature-property(TTP) curves and can determine properties based on the temperature histories. The constants($K_1{\sim}K_5$) of QFA were determined using hardness data obtained after various cooling rates. In the current study, a rear side member was selected for evaluation and FE-simulations were performed to obtain the temperature histories during hot stamping. The predicted temperature data were imported into the QFA to calculate the hardness distribution of the hot stamped parts. A hot stamping experiment of the rear side member was conducted to verify the predicted hardness. The simulation results show good agreement with the experimental measurements.

• Transactions of Materials Processing
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• v.19 no.6
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• pp.378-386
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• 2010

Nowadays there has been great interest in using heat treated cast material for press dies due to several advantages like reduction in die production costs. However, in hot press forming processes H13 forged tool steel is mostly used. Cooling performance of dies in hot press forming processes is considered as an important factor of study and also the IHTC parameter between cast material die and sheet metal should be considered as an essential. In the present study, the IHTC was calculated for the sheet metal in the hot press forming process with cast and forged material dies. The temperature measurements were performed for the sheet metal, casting and forged material dies by applying various contact pressure in hot press forming. IHTC was calculated and studied by adopting the inverse heat convection method in DEFORM-2D. Each IHTC was considered as a function of contact time and contact pressure. The experimental data were compared with calculated data obtained from the proposed equation and references.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.21-27
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• 2013

In recently years, with the growth of social media and the development of mobile devices, the data have been significantly increased. Hadoop has been widely utilized as a typical distributed storage and processing framework. The tasks in Mapreduce based on the Hadoop distributed file system are allocated to the map as close as possible by considering the data locality. However, there are data being requested frequently according to the data analysis tasks of Mapreduce. In this paper, we propose a hot-data replication mechanism to improve the processing speed of Mapreduce according to data access patterns. The proposed scheme reduces the task processing time and improves the data locality using the replica optimization algorithm on the high access frequency of hot data. It is shown through performance evaluation that the proposed scheme outperforms the existing scheme in terms of the load of access frequency.