• Transactions of the Society of Information Storage Systems
• /
• v.2 no.4
• /
• pp.230-235
• /
• 2006

The machine locking system is an important device for the safety of persons using the machine. In this study, a locking system using electromagnetic fields is proposed to decrease the defects and the cost for repairing and maintenance of the existing locking system using structural mechanism. We analyze the electromagnetic locking system and calculate the generated force considering direction by the finite element method. Also, we set up two design domains for the topology optimization; first domain is optimized to reduce the volume and the other is optimized to maximize the generated force keeping the volume, especially. The optimal design is obtained by integration of the two optimized results. An improved design is obtained by the optimal topology and it is confirmed by comparison with the initial locking system.

• International Journal of Fluid Machinery and Systems
• /
• v.4 no.1
• /
• pp.104-113
• /
• 2011

The paper presents a new method for the analysis of the cavitation behaviour of hydraulic turbomachines. This new method allows determining the coefficient of the cavitation inception and the cavitation sensitivity of the turbomachines. We apply this method to study the cavitation behaviour of a large storage pump. By plotting in semi-logarithmic coordinates the vapour volume versus the cavitation coefficient, we show that all numerical data collapse in an exponential manner. By analysis of the slope of the curve describing the evolution of the vapour volume against the cavitation coefficient we determine the cavitation sensitivity of the pump for each operating point.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.13 no.12
• /
• pp.1266-1274
• /
• 2001

Heat transfer phenomena during melting process of the phase change material (ice) was studied by numerical analysis and experiments. In a horizontal ice storage tube, the natural convection caused an increase in melting rate. However, the reduction of the heating surface area caused a decrease in melting rate. Therefore, during the melting process of ice in a horizontal cylinder, the reduction of the heating surface area should be considered. Under the same heating wall and initial water temperature condition, the melting rate became higher for $V_s/V_tot/=0.545 \;than \;that\; for\; V_s/V_tot$/=1.00 due to the difference in the reduction of heating surface area. A modified melting model considering the equivalent thermal conductivity of liquid phase and volume reduction was proposed. The results of the model were compared with the measured values and found to be in good agreement.

• Solar Energy
• /
• v.18 no.4
• /
• pp.59-66
• /
• 1998

It was compared with experimental data to verify TRNSYS Model of the thermosyphon hot water system and the various simulations were conducted to optimize the component parameters of the system. To obtain consistent simulation results the system model, which could accurately describ the thermal storage tank temperature stratification and the friction head for mass flow rate, was used. The optimization of collector parameters(collector aspect ratio, riser numbers per header unit length), thermal storage tank parameters(ratio of tank length to tank diameter, heat exchanger type), system parameters(ratio of tank volume to collector area) was simulated by TRNSYS program. The simulation results indicate that the system performance is more effected by collector aspect ratio and the ratio of tank volume to collector area than the othor parameters.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.2
• /
• pp.173-180
• /
• 2005

In this study, quantity and quality of collected rainwater by the ground collection system were investigated and the Rainwater Collection Prediction Model was developed to predict the amount of collected rainwater. The quantity of collected rainwater in the collection system was 9516 L(38.2%) and the quantity of infiltrated rainwater in the collection system was 9946 L(40.2%) through $25m^2$ area for the study period, respectively. Average turbidity of collected rainwater in collection system was 2.2 NTU, and average turbidity of infiltrated rainwater in collection system was 2.3 NTU for study period, respectively. The predicted amount by the model and the actual collected amount were 9842.4 L and 9516 L, which were very close showing that prediction was excellent. The optimal rainwater storage tank volume was simulated with a certain consumption condition for various cities with different rainfall patterns.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.14 no.3
• /
• pp.175-186
• /
• 1985

This paper presents a method for estimating the useful output of solar space heating system and estimates their performance with variance of collector size, storage volume, collector tilt and other factors . The analysis is performed by the computer simulation and by 'running' conceptual systems against solar intensities and ambient temperature for a model year stored in a computer. System performance is analyzed on monthly and yearly basis respectively and at the same time, the economics of various systems are evaluated . And also, this paper shows how an optimized design can be selected for any locality for which solar data, economic parameters and system performance are provided. It is shown that storage volume of 75 liter per $m^2$ of solar collector lead to the best design.

• International Journal of Computer Science & Network Security
• /
• v.24 no.7
• /
• pp.31-44
• /
• 2024

The inverted index is combination of the keywords and posting lists associated for indexing of document. In modern age excessive use of technology has increased data volume at a very high rate. Big data is great concern of researchers. An efficient Document indexing in big data has become a major challenge for researchers. All organizations and web engines have limited number of resources such as space and storage which is very crucial in term of data management of information retrieval system. Information retrieval system need to very efficient. Inverted indexing technique is introduced in this research to minimize the delay in retrieval of data in information retrieval system. Inverted index is illustrated and then its issues are discussed and resolve by implementing the scalable inverted index. Then existing algorithm of inverted compared with the naïve inverted index. The Interval list of inverted indexes stores on primary storage except of auxiliary memory. In this research an efficient architecture of information retrieval system is proposed particularly for unstructured data which don't have a predefined structure format and data volume.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.4
• /
• pp.520-529
• /
• 1998

Heat and mass transfer behaviors of metal hydride beds were predicted by solving a set of volume-averaged equations numerically both for the gas (hydrogen) and the solid(metal hydride) phases. Time variations of temperature and hydrogen concentration ratio distributions were obtained for internally cooled, cylindrical-shaped beds with metal(aluminum) fins imbedded in them. Also, time variations of the space-averaged hydrogen concentration ratio were obtained. Temperature and velocity of the coolant, hydrogen pressure at the gas inlet, and the fin spacing were taken as the parameters. The hydrogen absorption rate increases with the higher velocity and the lower temperature of the coolant, and with the decrease of the fin spacing. Increasing of the hydrogen pressure at the gas inlet also promotes the rate of absorption though the increasing rate gradually slows down. The amount of the hydrogen storage per unit volume of the bed decreases with the tighter fin spacing despite of the higher absorption rate ; therefore, there should be an optimum fin spacing for a given volume of the system and the amount of the hydrogen storage, in which the absorption rate is the highest.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2003.11a
• /
• pp.149-157
• /
• 2003

The HEPA filter waste (Hexahedron, $610{\times}610{\times}292mm$, 20kg), which is used for the ventilation system in the nuclear industries, has relatively large volume to compare with it's weight. Due to the large volume of HEPA filter waste, it needs the large storage and/or disposal space and managing cost during the long period of storage and management. Many countries use the compactor to reduce the volume of HEPA filter waste. On this paper we introduce the new type compactor developed by KAERI with the characteristical comparison to the Japan's and U.S.A's compactors.

• Journal of Information Processing Systems
• /
• v.15 no.1
• /
• pp.151-158
• /
• 2019

With the recent advances of memory technologies, high-performance non-volatile memories such as non-volatile dual in-line memory module (NVDIMM) have begun to be used as an addition or an alternative to server-side storages. When these memory bus-connected storages (MBSs) are installed over non-uniform memory access (NUMA) servers, the distance between NUMA nodes and MBSs is one of the crucial factors that influence file processing performance, because the access latency of a NUMA system varies depending on its distance from the NUMA nodes. This paper presents the design and implementation of a high-performance logical volume manager for MBSs, called MBS-LVM, when multiple MBSs are scattered over a NUMA server. The MBS-LVM consolidates the address space of each MBS into a single global address space and dynamically utilizes storage spaces such that each thread can access an MBS with the lowest latency possible. We implemented the MBS-LVM in the Linux kernel and evaluated its performance by porting it over the tmpfs, a memory-based file system widely used in Linux. The results of the benchmarking show that the write performance of the tmpfs using MBS-LVM has been improved by up to twenty times against the original tmpfs over a NUMA server with four nodes.