Jo Sep 11, 2026
OpenMP and MPI were preferred for parallel programming in the modes of shared memory and distributed memory, but now research has been focused on hybrid programming using both MPI and OpenMP and Apache Spark programming, which targets fast big data analysis.
Commonly, however, configuring a cluster environment requires more time than programming, and moreover, the difference between MPI-OpenMP of a parallel system using C language and Apache Spark of a distributed system using Java is one of the challenges to anyone who are not familiar with configuring Linux cluster as well as deploying Apache Hadoop stack.
Kim Ryo Chol, a section head at the Faculty of Information Science and Technology, proposed an integrated platform in which MPI-OpenMP and Spark parallel programming are both possible.
Virtual machines needed for parallel computation are provided by the private cloud based on OpenStack IaaS.
Applying the proposed method, he built an integrated platform for parallel programming, thus reducing the time for cluster environment configuration.
For more information, please refer to his paper “An Integrated Platform Architecture for MPI-OpenMP and Spark Parallel Programming on Cloud Environment” in “Proceedings of KUTIC-2025”.
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Jo Sep 10, 2026
The use of ozone gas started about a century ago and it has been used to purify water polluted by microorganisms. The chemistry of ozone in aqueous solutions is complex, and the direct reaction with molecular ozone and the indirect reaction with radicals generated when ozone is dissolved in water are considered for the process of water treatment with ozone. The direct and indirect reaction pathways of ozone generate different oxidation products and they are controlled by different kinetics.
Direct reaction of ozone has been quite well understood by previous researchers. The studies of ozone reactions and decomposition are still active, and most researchers are working on kinetics. The exact analysis of ozone reactions is still difficult due to very complex ozone reactions and insufficient information on reaction kinetic constants.
In theoretical studies of the UV-induced destruction of ozone layers in the earth's atmosphere, some researchers performed calculations of the stability of ozone-water vapor complex. The previous studies dealt with the reaction between molecular ozone and water vapor, but no first-principles studies have been carried out on the case of ozone gas dissolved in water. Therefore, first-principles study of ozone decomposition in water is necessary to improve the efficiency of water treatment by ozone.
Choe Un Hwa, a researcher at the Faculty of Physics, has determined reaction pathways for enhancing the efficiency of ozonation through first-principles considerations of ozone decomposition in water.
She newly defined the transition state that might be found during ozone decomposition in water and carried out a quantitative chemical calculation of ozone decomposition reactions in water by using the density functional method (DFT/6-31G*).
The results showed that the relative probability of the reaction to obtain H2O2 + O2 among the four possible reactions between O3 and H2O in gas and water is high, which indicates that the improved oxidation of ozone can be used to improve ozonation efficiency.
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Jo Sep 9, 2026
Water is indispensable for human life and economic development, and therefore, water treatment is one of the primary technical processes essential for people’s living and the overall sectors of the national economy.
Desalination by electrosorption is a novel water treatment technique, which is a combination of electrochemical method and adsorption method of separation. It is employed to purify water by removing salts and other substances dissolved in water by using the adsorption of ions and charged particles in water when an electric field is applied to an electrode made of conductive adsorbent material.
The core of electrosorption technology is the selection of electrode material and the design of electrode structure. Carbon adsorbent materials such as activated carbon, activated carbon fibers, graphene, carbon nanotubes and carbon aerogels are used as electrode material.
Kim Chang Sok, a researcher at the School of Science and Engineering, calculated the desalination rate by electrosorption of activated carbon electrodes from the electrical double layer phenomena at the liquid interface and the characteristics of activated carbon, and investigated the main factors i.e. voltage, interelectrode distance, water flow rate and treatment time, influencing the desalination of groundwater by electrosorption using electrodes. On this basis, he determined the optimum electrosorption conditions.
When the voltage was 2V, the interelectrode distance 15mm, the water flow rate 4m3/(kg·h) and the time 45min, the electrical conductivity and the hardness decreased by 43.8% and 33.5%, respectively.
The results confirmed that water treatment by electrosorption is an effective method with high desalination and softening efficiency, low power consumption and no environmental pollution.
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Jo Sep 8, 2026
Running accuracy and stiffness of spindle units in a machine tool have a crucial influence on the accuracy and reliability of the whole machine. Fatigue life calculation of bearings in spindle units is important to ensure the good performance of spindle units and to design machine tools scientifically.
In order to predict the fatigue life of rolling bearings used in machine tools, the stresses generated at the contact surface of interface are needed. This stress distribution is mainly determined by the pressure acting on the contact surface. Accurate calculation of pressure distribution can be done by FEM, which considers not only the generator shape but also the length in the contact state. The calculation of pressure distribution requires great computational efforts, which is more important in the case of repeating the calculation of many contacts in complex rolling pairs than in the case of simple contacts.
In the previous studies, several methods were used for the fatigue life of bearings, but they failed to analyze the effect of the roll profile and ring misalignment on the bearing fatigue life in a direct way.
Having developed a mathematical model for the fatigue life calculation of cylindrical roller bearings widely used in machine tool spindles, Kim Myong Il, a researcher at the Faculty of Mechanical Science and Technology, proposed a reasonable roller profile by calculating the fatigue life of bearings of three roller profiles and comparing them by FEM.
The results showed that the stress distribution is significantly lower for circular or logarithmic correction than for rectilinear roller generators, but the stress distribution is higher for circular correction, and the overall logarithmic correction significantly improves the fatigue life by 4.5 times.
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Jo Sep 7, 2026
High-grade copper-bearing ores have been increasingly depleted and instead, low-grade and complex ores have now become dominant in copper production. The existing production process for low-grade copper molybdenum ore has the disadvantage of high cost and high energy consumption. Therefore, a great deal of attention is being paid to the simple and environmentally-friendly bioleaching. Without proper heap bioleaching technology, millions of tonnes of low-grade copper ore might be left as waste.
While many studies have been carried out on the bioleaching of chalcopyrite, which is the main copper-bearing material, few studies have been reported on the direct bioleaching of complex minerals containing chalcopyrite.
Cha Kwang Chon, a post-graduate student at the Faculty of Mining Engineering, investigated the feasibility of bioleaching for copper recovery from low-grade, complex chalcopyrite in a column reactor.
The ore mainly contains pyrite and chalcopyrite as sulphide minerals and quartz as the main gangue minerals.
He carried out the tests in a column reactor using a mixture of inoculums used for bioleaching of pyrite.
The results showed that the dissolution of copper reached 85% after 120 days at 35-45℃.
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Jo Sep 4, 2026
The water electrolysis technology using proton exchange membranes (PEM) has now become more widespread in its use due to its simple operation and maintenance and high productivity per unit volume as an intensive and high-efficiency water electrolysis technology that can directly produce high-purity, high-pressure hydrogen without special ancillary devices. Despite these advantages over alkali water electrolysis technology, which is widely industrialized across the world now, its disadvantage is high cost. It is attributable to the high cost of proton exchange membranes and electrode catalysts for them.
Ho Kuk Chol, a post-graduate student at the Institute of Nano Science and Technology, prepared ATO-supported IrO2-RuO2 composite catalysts as anodic catalysts in PEMWE by using the Adams method and investigated their electrochemical and water electrolytic properties.
When the Ir content was 30% for the IrO2-RuO2 composite catalyst and 80% for the supported catalyst, the catalysts had current density of 77.5mA/cm2 at the voltage of 1.5V in 0.5mol/L H2SO4 solution. The stability experiments in the same solution showed that the supported composite catalyst had almost the same stability as IrO2. It was concluded that the prepared catalyst showed almost the same performance with 60% reduction in cost compared to IrO2 catalysts.
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