• Membrane Journal
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• v.23 no.2
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• pp.159-169
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• 2013

The effect of humic acid (HA), and the roles of microfiltration (MF), PES (polyethersulfone) beads adsorption, and photo-oxidation were investigated in hybrid process of ceramic MF and PES beads loaded with titanium dioxide ($TiO_2$) photocatalyst for advanced drinking water treatment. The results of water and nitrogen back-flushing were compared in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). Because membrane fouling increased dramatically as increasing HA, Rf increased and J decreased, and finally $V_T$ was the highest at 2 mg/L HA. Average turbidity treatment efficiencies were almost same independent of HA concentration. Average organic matter treatment efficiency was the minimum 71.4% at 10 mg/L HA in water back-flushing, but those were almost constant in nitrogen back-flushing. The hybrid process of MF, PES beads, and UV (MF + $TiO_2$ + UV) have the lowest $R_f$, and the highest J and $V_T$ in both water and nitrogen back-flushing. The turbidity and organic matter treatment efficiencies were the maximum at MF + $TiO_2$ + UV independent of water and nitrogen back-flushing, and decreased sequently as simplifying the process to MF. However, adsorption performed the more important role than photo-oxidation in water back-flushing, and photo- oxidation was the more than adsorption in nitrogen back-flushing.

• Analytical Science and Technology
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• v.18 no.4
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• pp.344-354
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• 2005

This study was carried out to evaluate the performance of a small chamber sampling and analytical method for the measurement of total volatile organic compounds (TVOC) and formaldehyde (HCHO) emission from building materials. While VOC was determined by the adsorbent tube sampling and sequential thermal desorption coupled with GC/MSD analysis, formaldehyde sampled with DNPH-silica cartridge was analyzed by HPLC. Wide-range performance criteria such as repeatability, desorption efficiency, emission chamber recovery test, duplicate precision, breakthrough volume and method detection limits were investigated for the evaluation of small chamber method. The overall precision of the small chamber sampling and analytical methods was estimated within 20~30% for target compounds. In conclusion, this study demonstrated that the small chamber sampling and analytical method can be reliably applied for the measurement of building materials pollutants.

• Science of Emotion and Sensibility
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• v.5 no.2
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• pp.29-34
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• 2002

Our previous studies investigated that narrow field of view (FOV : 50˚) and slow navigation speed decreased the frequency of occurrence and severity of cybersickness during immersion in the virtual reality (VR). It would cause a significant reduction of cybersickness if it were provided cybersickness alleviating virtual environment (CAVE) using biofeedback method whenever subject underwent physiological agitation. For verifying the hypothesis, we constructed a real-time cybersickness detection and feedback system with artificial neural network whose inputs are electrophysiological parameters of blood pulse volume, skin conductance, eye blink, skin temperature, heart period, and EEG. The system temporary provided narrow FOV and decreased speed of navigation as feedback outputs whenever physiological measures signal the occurrence of cybersickness. We examined the frequency and severity of cybersickness from simulator sickness questionnaires and self-report in 36 subjects. All subjects experienced VR two times in CAVE and non-CAVE condition at one-month intervals. The frequency and severity of cybersickness were significantly reduced in CAVE than non-CAVE condition. Virtual environment of narrow FOV and slow navigation provided by electrophysiological features based artificial neural network caused a significant reduction of cybersickness symptoms. These results showed that efficiency of a cybersickness detection system we developed was relatively high and subjects expressed more comfortable in the virtual navigation environment.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.67-71
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• 2013

$FeCl_3$ has been used as an etchant for metal etching such as Fe, Cu, and Al. In the process of metal etching, $Fe^{3+}$ is reducted to $Fe^{2+}$ and the etching rate becomes slow and etching efficiency decreased. Waste $FeCl_3$ etchant needs to be regenerated because of its toxicity and treatment cost. In this work, HCl was initially mixed with the waste $FeCl_3$ and then, strong oxidants, such as $O_2$ and $H_2O_2$, were added into the mixed solution to regenerate the waste etchant. During successive etching and regeneration processes, oxygen-reduction potential (ORP) was continuously measured and the relationship between ORP and etching capability was investigated. Regenerated etchant using a two vol% HCl of the total etchant volume and a very small amount of $H_2O_2$ was very effective in recovering etching capability. During the etching-regeneration process, the same oxygen-reduction potential variation cannot be repeated every cycle since concentrations of $Fe^{2+}$ and $Fe^{3+}$ ions were continuously changed. It suggested that the control of etching-regeneration process based on the etching time becomes more efficient than that of the process based on oxygen reduction potential changes.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.8
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• pp.1231-1239
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• 2007

The purpose of this study was to investigate consumer's behaviors on the laundering of baby's clothing according to washing machine types. The subjects were 255 consumers with babies(0-2 years) in Korea. The data were collected with a self-administered questionnaire and analyzed by Chi-square test and multiple response analysis, and SPSS 12.0 statistics package was used. Consumers were separated into two groups according to washing machine types with general pulsator type and drum-type. Consumer's behaviors between general pulsator type group and drum-type group of washing machines were also examined. The results of this study were as follows. In the consumer satisfaction for washing machine, mostly drum-type group of consumers were satisfied with their washing machines. As the reasons of washing machine's dissatisfaction, noise, washing time and low washing efficiency were high in the pulsator type group, and washing time, noise and high price in the drum-type washing machine group. The consumers concerned about separation of clothing and laundering label while they washed laundry by washing machine. However, they didn't separate clothing because the small volume of laundry and a long washing time. The most interest and required thing of consumers was complete rinsing without any detergents used in washing as well as the removal of soils for baby's clothing regardless of two washing machine types. And they complained food soils like milk and mother's milk etc. were not completely removed by washing machine. As a whole the washing frequency of baby's laundry was once per a day and the rinsing also more than three times per a laundry. Most of the consumers used a private detergents for baby's clothing(detergents for baby's clothing only), and preferred to the high or boiled temperature washing as a desirable baby's laundering. There were significant differences between general pulsator type group and drum-type group of washing machines on the laundering of baby's clothing in this study.

• Fire Science and Engineering
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• v.24 no.3
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• pp.131-138
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• 2010

Experimental and numerical studies were conducted to investigate the thermal and chemical characteristics of heptane fires in a full-scale ISO 9705 room. Representative fire conditions were considered for over-ventilated fire (OVF) and under-ventilated fire (UVF). Fuel flow rate and doorway width were changed to create OVF and UVF conditions. Detailed comparisons of temperature and species concentrations between experimental and numerical data were presented in order to validate the predictive performance of FDS (Fire Dynamic Simulator). The OVF and UVF were explicitly characterized with distributions of temperature and product formation measured in the upper layer, as well as combustion efficiency and global equivalence ratio. It was shown that the numerical results provided a quantitatively realistic prediction of the experimental results observed in the OVF conditions. For the UVF, the numerically predicted temperature showed reasonable agreement with the measured temperature. The predicted steady-state volume fractions of $O_2$, $CO_2$, CO and THC also agreed quantitatively with the experimental data. Although there were some limitations to predict accurately the transient behavior in terms of CO production/consumption in the UVF condition, it was concluded that the current FDS was very useful tool to predict the fire characteristics inside the compartment for the OVF and UVF.

• Journal of Families and Better Life
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• v.33 no.4
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• pp.19-32
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• 2015

The purpose of this study is to examine the influence of the organizational characteristic and workers characteristics of Family Business Organization on its Business Performance. The subjects of this study were workers of healthy family support centers and multicultural family support centers. A survey was conducted from July 30th to September 30th. A total 372 materials were used for analysis of final data and SPSS(Statistical Package for the Social Sciences) WIN 18.0 program was employed in analyzing the collected data. As the result of analysing the effect of organizational characteristics and culture and characteristics of workers on business performance through hierarchical regression analysis, higher performance was achieved when the agency's organizational culture has the characteristics of a developed culture, and when the operating body is a school principal corporation rather than a non-profit corporation, and in the city rather than farming town, having enough information and external resources at the center, and when the job satisfaction of workers are high, and when organizational culture is more hierarchical. There were difference in the result of analysing the effect of organizational characteristic and culture and characteristic of workers on business performance. The level of service and business value of Family Service Organization was higher when the agency's organizational culture has the characteristics of a developed culture, hierarchical culture and agreement culture, and when operating body is a school principal corporation rather than a non-profit corporation, having enough information and external resources at the center, and the administrative skills of workers are higher. Business volume is increased when the operating body is a school principal corporation rather than a non-profit corporation, and in the city rather than farming town, and when the agency's organizational culture has the characteristics of hierarchical culture and agreement culture, having enough external resources at the center, and the practicing ability of workers are higher. When it comes to business efficiency, it is increased when the agency's organizational culture has the characteristics of developed culture and the job satisfaction of workers are high, having enough external and financial resources at the center. Therefore we will need to enhance business performance through improved management and job satisfaction of employees in organizational culture.

• Journal of Aquaculture
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• v.16 no.3
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• pp.142-150
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• 2003

Performance of a biological filter, the rotating biological contactor (RBC), is affected by rotational speed and hydraulic residence time (HRT). A RBC with a disc diameter of 62 cm, total surface area of 48.28 $m^2$, volume of 0.34 ㎥, and submergence ratio of 35.4% was tested for the combinations of five rotational speeds (1, 2, 3, 4 & 5 rpm) and three HRT (0.5, 1.0 & 2.0 hr) to find out the maximum removal efficiencies of total ammonia nitrogen (TAN) and nitrite nitrogen of a simulated recirculating aquaculture system. Ammonia loading rate in the system was 25 g of TAN/ ㎥. day. Removal efficiencies were checked when TAN concentrations in the system stabilized for 3 days in each treatment. The concentration of TAN in the system decreased with increasing rotational speed of the RBC up to 4 rpm in all HRT (P<0.05). At the rotational speed of 5 rpm, the efficiencies decreased in all HRT (P<0.05). When the rotational speeds were 1, 2, 3, 4, and 5 rpm, TAN concentrations in the system were 1.35, 0.94, 0.69, 0.66, and 0.76 mg/L at the 0.5 hr HRT, 2.86, 1.18, 0.96, 0.87, and 1.11 mg/L at the 1.0 hr HRT, and 5.30, 2.44, 1.99, 1.77, and 2.01 mg/L at the 2.0 hr HRT, respectively. The TAN removal efficiencies of the RBC at the rotational speeds of 1, 2, 3, 4, and 5 rpm were 32.9, 49.5, 65.1, 72.9, and 62.9% in 0.5 hr HRT,33.1, 74.1, 87.1, 95.8, and 78.5% in 1.0 hr HRT, and 35.5, 76.7, 89.6, 97.0, and 85.5% in 2.0 hr HRT, respectively. TAN removal efficiency of RBC per pass increased with increasing HRT. However, TAN concentration in the system also increased. The best operating condition among the treatments was obtained at the treatment of 0.5 hr HRT and 4 rpm (P<0.05). The TAN concentration was 0.66 mg/L. Concentrations of nitrite nitrogen (NO$_2$$^{[-10]}$ -N) in the system decreased with increasing rotational speed in all HRT while that in the system increased with increasing HRT in all rotational speeds. The ranges of NO$_2$$^{[-10]}$ -N concentrations at HRT of 0.5, 1.0, and 2.0 hr in the system were 0.26~0.32, 0.31~0.56, and 0.43~l.45 mg/L, respectively. The ranges of daily removal rates of TAN in this system were 20.03~23.0 g TAN/㎥ㆍday and those of nitrite nitrogen were 19.65~30.25 g NO$_2$$^{[-10]}$ -N/㎥ㆍday.

• Journal of the Korea Society of Computer and Information
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• v.16 no.6
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• pp.21-30
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• 2011

In the global IT market, a lot of issues for responding to various environmental regulations emerged. In case of the data centers, it is consuming huge amounts of energy to maintain. So there have been various technical attempts as Consolidation, Virtualization, Optimization to efficiently manage energy and data storage to fix the problems. In this paper, we propose a new RAID(Redundant Array of Independent Disks) mechanism which is differing the intensity of power consumption and works to provide data protection and disaster recovery(backup, mirroring etc.) to stratify multiple volumes. G-RAID minimize the power consumption and the lower of I/O performance by selecting the volume depending on the frequency of data access while classifying the power consumption between volumes in storage system. Also, it is possible that a filesystem and block map information of G-RAID is processed by basic unit which is group located in a row for the blocks to work efficiently and can minimize the performance degradation of block mapping load by the access frequency in each groups. As a result, we obtained to elevate a little bit of response time caused by block relocation work, but showed the decrease of power consumption by 38%.

• Journal of Korean Society of Archives and Records Management
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• v.18 no.1
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• pp.129-154
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• 2018

It is time to prepare for the imminent development from the field of records management through decentralization to the records management of the new age in accordance with the flow of decentralization. To overcome a centralized record management system, more archives should be established to realize autonomous and decentralized records management. In accordance with the shift to a full-scale electronic record management environment, the appropriateness and effectiveness of the three-phase system of processing-archival-permanent record management based on physical transfer should be reviewed in terms of transfer cost and work efficiency. The archives should function as institutional archives to carry out the continuous volume record management and the autonomous record management at the institution level. This study examined the possibilities and implications of the archives to expand their functions as archives of institutions for the decentralization of record management and information governance orientation. In addition, the study diversified the types of records management institutions as a way to accomplish this and determined a way to design the functions of archives that integrate the current-end-end-end records management. At each level, institutions should set up archives based on their circumstances and aim at information governance at the level of each archive. Moreover, each archive level should establish a horizontal network to govern record information management.