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A modified charcoal kiln was developed for both thermal therapy and charcoal production. The design of a modified kiln for thermal therapy focused on safety and cleanliness, plus the production of good quality charcoal. Two entrances in the kiln were designed for convenient charcoal production and thermal therapy. A barrier wall designed for noxious gases was installed between the adjoining charcoal kilns for safe thermal therapy. Additionally, a fine dust collector was installed to remove the fine dust generated during charcoal production. To verify the safety of the kiln, fine dust and harmful gases, such as carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2), and radon (Rn), were measured after the charring process. The quality of the charcoal produced in the thermal therapy kiln was also examined. To evaluate charcoal quality, some physical properties and results from a proximate analysis were evaluated using Korean standards. The measurements of harmful substances and fine dust in the modified charcoal kiln met the criterion of the Ministry of Environment Clean Air Conservation Act in Korea. In addition, there were no noticeable differences in the monthly charcoal characteristics prepared from the thermal therapy kiln, and the charcoal characteristics also met the reference values of the Korea Forest Service.

Fe is considered as one of the most harmful trace elements among impurities in aluminum and its alloys due to its influence of the mechanical properties especially in elongation. It is therefore essential that the Fe content is controlled to improve quality and the toughness of aluminum alloy castings. Since demand for high strength aluminum alloy casting was significantly increased in electro materials and devices, automotive and airplane industries, it is necessary to characterize the effect of Fe and set the tolerable amount of Fe content in aluminum alloys. Al6061 alloys were prepared with compositions of 0.36, 0.45, 0.58, 0.65, 0.75, 0.81 and 0.91 wt.% Fe. Solidification characteristics were analyzed by CALPHAD (Pandat software) method. Mechanical properties such as hardness, tensile strength, elongation and fatigue strength were evaluated and compared with different Fe contents. Al13Fe4 phase increased with increasing as Fe content, however, other phases, α-AlFeSi and Mg2Si, showder a slight decrease. The higher the Fe content, the lower the electrical conductivity of the alloy due to the severe distortion of the Al matrix. As Fe content was more than specification of Al6061 alloy, 0.7 wt.%, the mechanical properties, especially, hardness and elongation were greatly influenced. The hardness is attributed to the poor densification and angular-shaped Al13Fe4 phases unevenly distributed in the α-Al matrix.

The hot deformation characteristics of an UNS No. S32205 grade duplex stainless steel with nitrogen content of 0.17 ms% was studied over the ranges of temperature from 800 to 1200 °C and strain rates from 0.001 to 1.0 s−1 at the total strain of 0.5 by the hot compression test to draw the processing map. The obtained map was discussed in combinations of microstructural observations and TEM analysis. The optimum hot working region is the temperatures from 950 to 1200 °C regardless of the strain rates without cracks and sigma precipitates.

Objective The risk of complications is high for patients with a large cranial defect and hydrocephalus, undergoing cranioplasty and ventriculoperitoneal (VP) shunt operation. The purpose of this study is to examine retrospectively such cases with complications and contrive an operative technique to reduce complications. Methods Nineteen patients underwent cranioplasty and VP shunt operation due to large cranial defects and hydrocephalus. These patients were divided into two groups: Group A with 10 patients who underwent staged-operations, and Group B with 9 patients who underwent one-stage operation. Their complications in each group were retrospectively reviewed. Another five patients underwent a one-stage operation with temporary occlusion of the distal shunt catheter to improve on the technique and were categorized as Group C. Complications in these groups were compared and analyzed. Results The results of the data analysis revealed that complications related to anesthesia (40%) and those related to antibiotic prophylaxis (30%) were high in Group A, while non-infectious delayed complications (45%) and perioperative complications such as intracranial hematoma (33%) were high in Group B. However, for patients in Group C, it showed less complication with the operative technique devised by these authors, as opposed to two previous procedures. Conclusion In patients with hydrocephalus and a large cranial defect, complications arising from existing one-stage operation or staged-operations can be reduced by implementing the technique of "one-stage operation with temporary occlusion of the distal shunt catheter."

Owing to the focal wall defect covered with thin fibrous tissues, an aneurysm arising from the dorsal wall of the internal carotid artery (ICA) is difficult to manage either surgically or endovascularly and is often associated with high morbidity and mortality. Unfortunately, the definitive treatment modality of such highly risky aneurysm has not yet been demonstrated. Upon encountering the complex intracranial pathophysiology of such a highly precarious aneurysm, a neurosurgeon would be faced with a challenge to decide on an optimal approach. This is a case of multiple paraclinoid aneurysms including the ICA dorsal wall aneurysm, presented with spontaneous subarachnoid hemorrhage. With respect to treatment, direct clipping with a Sundt graft clip was performed after multiple endovascular interventions had failed. This surgical approach can be a treatment modality for a blood blister-like aneurysm after failed endovascular intervention(s).

The management guideline for traumatic brain injury (TBI) recommends high-dose barbiturate therapy to control increased intracranial pressure refractory to other therapeutic options. High-dose barbiturate therapy, however, may cause many severe side effects; the commonly recognized ones include hypotension, immunosuppression, hepatic dysfunction, renal dysfunction, and prolonged decrease of cortical activity. Meanwhile, dyskalemia remains relatively uncommon. In this study, we report the case of a hypokalemic patient with severe rebound hyperkalemia, which occurred as a result of barbiturate coma therapy administered for TBI treatment.

Korea is expected to one of countries with water shortages, and thus must secure high-quality water resources and strictly maintain them. However, water is frequently polluted and there is still a lack of water treatment technologies and facilities to provide safe water. To remove pollutants, membrane-based methods are being widely used for water treatment. It needs high pressure and energy to capture the pollutants by pore size. In this study, electrostatic force is used to increase the efficiency of filtration and decrease pressure loss. By electro spinning, nanoelectret filter is made with 100 nm in diameter and positive charge potential. Surface potential is measured by electrostatic voltmeter system with nanoelectret filter by three conditions of applied voltage. For the filtration performance, filtration efficiency is measured by filter test system with 0.5 and 1.0 PSL. Also pressure loss of nanoelectret filter is measured by comparing PC membrane.

Recently, demand of aluminum alloys for manufacturing in components with high thermal conductivity application increases. However, the most aluminum die casting alloys exhibit very lower thermal properties, about only a half of pure aluminum. In die casting alloys, alloying elements are essential to obtain sufficient fluidity and mechanical strength, therefore, in this study, the effect of alloying elements, Si, Cu, Mg, Fe and Mn, on thermal conductivity, die casting characteristics and mechanical properties were analyzed and the appropriate amount of each alloying element were investigated. The results showed that Mn had the most deleterious effect in thermal conductivity and Si and Fe contents were important to improve fluidity and strength. The alloy with 1.5~2.0wt.%Si and 0.6wt.%Fe showed very good combination of high thermal conductivity and sufficient casting characteristics.

It is generally known that silicon influences the fluidity of aluminum alloys. There are several techniques to evaluate the fluidity of aluminum for gravity casting such as using spiral or serpentine type mold and vacuum suction test. However, fluidity of aluminum in high pressure die-casting has not been sufficiently studied. Therefore, in this study, the relationship between the fluidity and superheat of pouring aluminum alloy as well as injection speed was studied. A serpentine and step type die for evaluating the fluidity of aluminum alloys was designed and actual experiments were conducted for aluminum by varying many parameters such as pouring and injection speed and the content of silicon. The results showed that fluidity of aluminum in die-casting was quite similar to the gravity casting. Under high pressure die casting conditions, increased fluidity was measured as the silicon content, superheat, G.B.F treatment time and injection speed were increased.

In order to investigate corrosion and soldering behaviour of STD61, TiN and TiAlN were coated on the surface of STD61 by using Arc Ion Plating. The structure of the coatings was examined as a function of deposition conditions by X-ray diffraction, and the crystallographic orientation was determined by use of a texture coefficient. TiN coating was grown with a strong (111) preferred orientation of a typical NaCl-type crystal structure. This strong (111) preferred orientation had been commonly observed from the TiN coatings deposited by physical vapour deposition techniques. TiAlN coatings, however, showed relatively multiple orientations mainly of (111) and (200). Furthermore, TiAlN film demonstrated superior corrosion resistance in a molten aluminum alloy at 680°C. This paper described in detail the corrosion and mass loss phenomena related to this steel-cast metal interaction.

The microstructure and mechanical behaviors of the Al-Mg-B ternary alloy have been investigated in order to fabricate a composite system composed of (Al,Mg)B2 in a Al-Mg matrix. Several Al-Mg-B ternary alloy compositions were selected for identification of borides and matrix formation during solidification. The in-situ (Al,Mg)B2 phase was developed in an eutectic matrix of Al8Mg5 and Al, and formed in the location of inter and intra the Al dendritic region, indicating that the formation of (Al,Mg)B2 was developed at the initial solidification process. Dominating factors for controlling the (Al,Mg)B2 phase and mechanical behaviors are discussed in terms of structural identifications.

It is important to establish water treatment technologies for drinking water because Korea belongs to water-stressed country. Leachate from recent incident of foot-and-mouth disease has become an opportunity to be aware of the need to manage water quality. Water purifiers are adopted to four or five steps of filtration process. Each steps are composed of a sediment filter, a pre-carbon filter, an UF or a RO membrane filter and a post-carbon filter. And additionally a ceramic filter can be used as a final stage. In this study, operational conditions in each steps are examined and characteristics of each filters are investigated. SEM analysis is used for filter surface and shape investigation using 6 commercial samples. Pore sizes of the sediment filter, the UF membrane filter, and the RO membrane filter are 30~47 , 0.005~0.5 , and 0.025~0.25 , respectively. Specific surface areas of activated carbons are ranged from 622 to 1,308 .

Advanced Encryption Standard (AES) has replaced its predecessor, Double Encryption Standard (DES), as the most widely used encryption algorithm in many security applications. Up to today, AES standard has key size variants of 128, 192, and 256-bit, where longer bit keys provide more secure ciphered text output. In the hardware perspective, bigger key size also means bigger area and power consumption due to more operations that need to be done. Some companies that employ ultra-high security in their systems may look for a key size bigger than 256-bit AES. In this paper, 128 and 256-bit AES hardware, as well as two variants of an AES encryption algorithm for 512-bit and 1024-bit key size, are implemented and compared in terms of power consumption and area. The experiment is done in 45 nm CMOS technology at 1.1 V using a Synopys DC Compiler and Modelsim and total power consumption and area results are presented and graphically compared.

The effects of Mg and Si contents on the microstructure and mechanical properties in Al-Mg alloy (ALDC6) were investigated.The results showed that phase fraction and size of Mg 2 Si and Al 15 (Fe,Mn) 3 Si 2 phase in the microstructure of Al-Mg alloy wereincreased as the Mg and Si contents were raised from 2.5 to 3.5wt%. With Si content of 1.5wt%, freezing range of the alloy wassignificantly reduced and solidification became more complex during the final stage of solidification. While there was no significantinfluence of Mg contents on mechanical properties, Si contents up to 1.5wt%, strongly affected the mechanical properties. Espe-cially elongation was reduced by about a half with more than 1.0wt%Si in the alloy. The bending and impact strength weredecreased with increased amount of Si in the alloy, as well. The lowered mechanical properties are because of the growth of particleshaped coarse Mg 2 Si phase and precipitation of the needle like β -AlFeSi in the microstructure at the last region to solidify due topresence of excess amount of Si in the alloy.Key words : Al-Mg alloy, Die casting, Mechanical property, Microstructure, Thermodynamic simulation, Alloying element effect.

The recent trends in malwares show the most widely used for the distribution of malwares that the targeted computer is infected while the user is accessing to the website, without being aware of the fact that, in which the harmful codes are concealed. In this thesis, we propose a new malicious web page detection system based on a real time analysis of normal/abnormal behaviors in client-side. By means of this new approach, it is not only the limitation of conventional methods can be overcome, but also the risk of infection from malwares is mitigated.

Recent developments have caused the expansion of various cloud computing environments and services. Cloud computing environments have led to research in the areas of data processing, virtual environments, and access control. Information security is the most important research area for these environments security. In this study, we analyzed typical example of network testbeds, which have been used for malicious activity data collection and its subsequent analysis. Further, we propose an effective malicious network application testbed, which is based on a cloud system. We also verified the performance of our new testbed by comparing real malicious activity with the cloud-based testbed results.

The effect of the alloy systems Al-Mg alloy and Al-Si alloy in this study on the characteristics of die-casting were investigated using solidification simulation software (MAGMAsoft). Generally, it is well known that the casting characteristics of Al-Mg based alloys, such as the fluidity, feedability and die soldering behaviors, are inferior to those of Al-Si based alloys. However, the simulation results of this study showed that the filling pattern behaviors of both the Al-Mg and Al-Si alloys were found to be very similar, whereas the Al-Mg alloy had higher residual stress and greater distortion as generated due to solidification with a larger amount of volumetric shrinkage compared to the Al-Si alloy. The Al-Mg alloy exhibited very high relative numbers of stress-concentrated regions, especially near the rib areas. Owing to the residual stress and distortion, defects were evident in the Al-Mg alloy in the areas predicted by the simulation. However, there were no visible defects observed in the Al-Si alloy. This suggests that an adequate die temperature and casting process optimization are necessary to control and minimize defects when die casting the Al-Mg alloy. A Tatur test was conducted to observe the shrinkage characteristics of the aluminum alloys. The result showed that hot tearing or hot cracking occurred during the solidification of the Al-Mg alloy due to the large amount of shrinkage.

Machine Learning as network attack detection is one of the popular methods researched. Signature based network attack detection is no longer convinced the efficiency in the diversified intrusions (Limmer and Dressler in 17th ACM Conference on Computer and Communication Security, 2010). Moreover, as the various Zero-day attacks, non notified attacks cannot be detected (Wu and Banzhaf in Appl Soft Comput 10(1):1---35, 2010). This paper suggests an effective update method of data set on Machine Learning to detect non notified attacks. In addition, this paper compares and verifies the effects of Machine Learning Detection with updated data set to the former methods.

In network data analysis, research about how accurate the estimation model represents the universe is inevitable. As the speed of the network increases, so will the attacking methods on future generation communication network. To correspond to these wide variety of attacks, intrusion detection systems and intrusion prevention systems also need a wide variety of counter measures. As a result, an effective method to compare and analyze network data is needed. These methods are needed because when a method to compare and analyze network data is effective, the verification of intrusion detection systems and intrusion prevention systems can be trusted. In this paper, we use extractable standard protocol information of network data to compare and analyze the data of MIT Lincoln Lab with the data of KDD CUP 99 (modeled from Lincoln Lab). Correspondence Analysis and statistical analyzing method is used for comparing data.

Knowledge of the Mg–B binary phase diagram is important in for the synthesis of superconducting MgB2 and of potential, new Mg–B alloys. However, the literature phase diagram is highly uncertain because it was originally constructed by guessing the decomposition temperatures of magnesium boride phases. We therefore utilized the CALPHAD method and ab initio calculations to compute thermodynamic model parameters to determine the decomposition temperatures of magnesium borides and re-assess the Mg–B binary phase diagram.

The practical uses of soft magnetic composite(SMC) for an electrical motor is presented in this paper. SMC allows obtaining improved stator and core shapes as well as totally new design concepts such as claw pole motor. However, a major disadvantage of soft magnetic composites was their weak strength. In this study, spark plasma sintering (SPS) was utilized to improve the strength of SMC. Advantages of the SPS process over other conventional sintering process are the faster heating and cooling rates ensured and higher pressure applied during the sintering procedure. This allows obtaining high strength products in short periods of time to meet with industrial application without insulation destruction. This paper introduces the development of high strength soft magnetic composite motor core and examples of practical application for industries. The result showed that the SPS process increased the fracture strength, about 1.3 to 1.7 times, of SMC compare to the conventional compaction. Also we derive method to reduce the iron loss in the SPS sintering process using control forming temperature. As the forming temperature decreased from 500°C to 300°C, reduction of iron-loss was obtained from 192W/kg to 21W/kg by using SPS sintering process. Moreover, with increased the SPS sintering process pressure value from 250MPa to 800MPa which is the conventional compaction condition and decreased forming temperature to 200°C, iron-loss was measured. The results showed that iron-loss was obtained 11.42W/kg and it was similar value of conventional compaction results.

Aluminum foam is lightweight structures, energy absorption and thermal management. In this reason, there is a lot of attention on the aluminum foam as a structural material. The present papers showed various conventional joining techniques can be applied for foam-sheet structures, i.e., riveting, screwing, welding, gluing and soldering. This research presents new joining technique of Aluminum foam/Aluminum metal using spark plasma sintering (SPS) process. The Aluminum foam/Aluminum metals were fabricated by changing of various SPS holding temperature and holding time conditions. With increasing holding temperature and holding time, the tensile stress increased. The specimen sintered at 550°C for 20 min shows σts = 1.47 MPa. Also, it was found that the SPS holding time is dominant factor than the holding temperature for sound joining of two joint materials.

A quantitative study of the interactions between microstructural features such as secondary dendrite arm spacing (DAS), eutectic structure and fatigue behavior of two Al-Si-Mg casting alloys with silicon contents of 7% and 10% respectively, has been conducted. In the condition of minimizing casting defects, the influence of microstructural features on the mechanical performance becomes more pronounced. Depending on the magnesium content affecting the strength of the matrix, the tensile properties were changed upon experimental conditions; the tensile strength was increased with magnesium content, whereas the elongation was increased in the reverse case. The increase of both of high cycle fatigue and low cycle fatigue lives with decreasing the secondary dendritic arm spacing is observed, mainly due to homogeneous deformation owing to the fine size of eutectic silicon and Fe intermetallic particles. The fatigue dynamometer of a diesel cylinder head shows the same tendency with the results of specimen fatigue tests with microstructures.

A new life function based on a model for the creep–fatigue life prediction in terms of stress relaxation during hold time has been proposed. From the concept that the reduction of fatigue life with hold time is due to the creep effect of stress relaxation that results in the additional energy dissipation in the hysteresis loop, the relaxed stress range is suggested to be a creep–fatigue damage function. The plastic strain range (Δɛp) exhibiting a functional correlation of both strain and time requires experimental efforts following Coffin–Manson relationship [L.F. Coffin Jr., Trans. ASME 76 (1954) 931–950; S.S. Manson, NASA Technical Note 2933, NASA Research Center, Cleveland, OH, 1954] upon applied creep–fatigue conditions. After the new concept was applied to the relationship, all the Coffin–Manson plots at the various levels of hold time under strain-controlled fatigue tests were identified as a linear relationship with relaxed stress range (Δσ) and fatigue life (Nf). The normalized creep–fatigue life prediction model, which can be applied to high temperature materials regardless of the fracture morphology is presented in view of a real situation.

The fracture behaviors of laminated composites of bulk metallic glass (BMG (Vitreloy1))/crystalline layer have been examined via both experimental and simulation approaches. The specimen array of BMG/Zr/BMG by an electron-discharge bonding technique showed a completed bonding, and the fracture tests showed that when the number of BMG layer increases up to three layers, the fracture energy for the laminated specimen is increased. The simulation results of the laminated composite exhibited that the enhancement of fracture energy for the composites is mainly due to the shear stress distribution through the interface between BMG layers.

Although glass wool and polyurethane foam are the most widely used sound-absorber and insulating materials, there are some critical problems related to the environmental issues. In this reason, there is a lot of attention on the aluminum foam as a sound absorption material, therefore, in this research, sound absorption and transmission loss properties were studied. The results showed that low density aluminum foam performed better in both sound absorption and transmission loss and the properties were improved as increased air cavity and space.

N-type 0.05wt% SbI 3 -doped Bi 2 Te 2.85 Se 0.15 compounds were fabricated by gas atomizing and hot pressing. The as-fabricated powder consists of homogeneous Bi 2 Te 3 +Bi 2 Se 3 solid solution and a maximum theoretical density of 98.9% was obtained after hot pressing, resulting in improvement of compression strength up to 4-5 times of the conventionally prepared single crystal thermoelectric material. The values of the Seebeck coefficient for hot pressed specimens vertical of the pressing direction with small and large powder size were -178 and -218μV/K, respectively. The values of the electrical resistivity for hot pressed specimens vertical of the pressing direction with small and large powder with small and large powder size were 1.245 and 1.728×10 -5 Q m, respectively.

The aims of this study ares to investigate the microstructure evolution of AZ31 Mg alloys with normal rolling and cross rolling during the large strain hot rolling affects microstructure, texture and mechanical properties of AZ31 Mg alloy. In the microstructures of as-rolled both samples, twins are clearly apparent, small and recrystallized grains are visible along some grain boundary and twinned regions. The lankford values of large strain cross rolled sample obviously demostrate the higher average r-value and lower planar anisotropy value. The press formaility of large strain rolled Mg alloy might be improved due to control of texture and grain size by change of the rolling direction.

Porous Ti compacts were fabricated by spark plasma sintering (SPS) method and their Young's modulus and biocompatibility were investigated in this study. Ti powders were made from commercially available pure Ti (grade 2) using the plasma rotating electrode process (PREP) in an Ar atmosphere. Porous Ti compacts for biomedical applications were successfully fabricated in the porosity range from 5.1 to 39.2 vol%. Young's modulus of porous Ti compacts having porosity from 31 to 35 vol % is almost the same as that of human cortical bone. To investigate the biocompatibility of pure Ti, fibroblast-like L-929 and osteoblast-like MG-63 cells were cultured with the presence of the extract solution from pure Ti for 72 hours. The viabilities of cells cultured with the diluted extract solutions were almost the same compared to that of the control. Also, porous Ti compacts did not induce any morphologic damage of cells.

Anelastic behavior of a 9Al2O3·2B2O3 (AlBw) whisker reinforced aluminum composite has been examined through the measurements of the dynamic Young’s modulus and internal friction over a temperature range of 25 to 500°C at frequencies of 0.01, 0.05 and 0.1 Hz. A standard servo-hydraulic mechanical testing machine equipped with an infrared lamp heater was employed, but the dynamic measurement system therein was especially designed by assembling a scanning laser extensometer and a frequency response analyzer for detecting the amplitude and phase lag of strain in response to a sinusoidal time-varying stress. Two peaks of internal friction were observed over the ranges 100 to 250°C (LT peak) and 250 to 400°C (HT peak), together with marked decreases in the dynamic Young's modulus in the same temperature ranges. From a quantitative analysis of the experimental data, it is concluded that the HT peak phenomenon is due to grain-boundary relaxation, whereas the LT peak phenomenon is ascribable to the relaxation caused by stress-directed interfacial diffusion of Al atoms along the whisker-matrix interface.

In this study, the microsegregation effect of copper during solidification of A356.2 aluminum casting alloy was evaluated by using solidification simulation and a series of experimental works. Electron probe micro analysis (EPMA) and the computational simulation revealed clearly that copper as a solute element segregates during solidification and it becomes more significant as the solidification approaches its completion. This microsegregation effect of copper is due to accumulated copper solute ahead of the eutectic interface during solidification. Consequently, the presence of a higher content of copper in A356.2 aluminum casting alloy causes influence on the solidification characteristics of the alloy and forms copper enriched phases at the last region to solidify in the microstructures.

The silicon-based aluminum casting alloy and 2 different types of gate designs were used to investigate experimentally the fabrication feasibility of sound thin-wall case casting by diecasting process. While split type gate design had no defect, tangential type gate design resulted in cracks in the all obtained specimens. Electrolytic Oxide (PEO) coating was performed as a surface treatment process. Before the PEO coating treatments some die cast specimens were heat treated at the temperature of 323K and N2 atmosphere for 1hr to evaluate the effect of heat treatment. The result showed that hardness was improved after PEO coating, however, the effect of heat treatment was not significant.

The effects of cooling rate on the solidification behavior of Al-8.5%Si-3%Cu and Al-11%Si-3%Cu alloys were studied during high pressure die casting (HPDC). The HPDC experiment was conducted by using the dies with 3 steps for 3 different cooling rates. Because of the high in both melt temperature and pressure, it was difficult to obtain the temperature profile directly from HPDC specimen. Therefore, in this study, cylindrical bar castings with different diameter were poured to acquire the cooling curves at the solidification range of 15°C/s up to 100°C/s and then the microstructures were compared to estimate the cooling rate in HPDC. The solidification characteristics including liquidus/solidus temperature and dendrite arm spacing of each alloy and each cooling rate was analyzed and the results showed strong proportional relationship between dendrite arm spacing and cooling rate in HPDC. The results were also compared with the actual die casting specimens and MAGMA simulation.

The formation of intermetallic reaction layers was investigated for die soldering between a STD61 steel and aluminum alloy. It is generally well known that Mn contents have advantageous effect on decreasing die soldering especially with aluminum alloys containing substantial amount of Si. However, die soldering has not widely studied for the low Si aluminum (1~2wt.%) alloys. Each aluminum alloy had melted then STD61 substrate was dipped in the melt for 2hr. The result from dipping soldering test showed the Al-Fe intermetallic layer in the microstructure. In Al-1wt.%Si alloy, additional content Mn also increased the thickness of the intermetallic layer compare to the alloy without Mn.

Aluminum rotor prone to have many casting defects especially large amount of air and shrinkage porosity, which caused eccentricity, loss and noise during motor operation. Many attempts have been made to develop methods of shrinkage porosity control, but still there are some problems to solve. In this research, the process of vacuum squeeze die casting is proposed for limitation of defects. The 6 pin point gated dies which were in capable of local squeeze at the end ring were used. Influences of filling patterns on HPDC were evaluated and the important process control parameters were high injection speed, squeeze length, venting and process conditions. By using local squeeze and vacuum during filling and solidification, air and shrinkage porosity were significantly reduced and the feeding efficiency at the upper end ring was improved 10%. As a result of controlling the defects, the dynamometer test showed improved motor efficiency by more than 4%.

Since mobile application market drastically extended, there have been many problems related to proliferative malicious applications that leak user’s private information stored in own smart device. In Korea, government strives to protect smart device users from these problems and to establish legal basis through ‘Privacy Act’ as a preceding step but studies on analysis models and verification tools for mobile application have not yet much developed. The purpose of this research is to suggest an analysis system to prevent propagation of harmful applications, which compromise the user’s personal information, by extracting signatures from malicious code samples detected in Android. Maliciousness of the applications has determined by learning their parsing information on the components such as DEX, Manifest, SO etc.

Network data sets are often used for evaluating the performance of intrusion detection systems and intrusion prevention systems[1]. The KDD CUP 99’ data set, which was modeled after MIT Lincoln laboratory network data has been a popular network data set used for evaluation network intrusion detection algorithm and system. However, many points at issues have been discovered concerning the modeling method of the KDD CUP 99’ data. This paper proposed both a measure to compare the similarities between two data groups and an optimization method to efficiently modeled data sets with the proposed measure. Then, both similarities between KDD CUP 99’ and MIT Lincoln laboratory data that between our composed data set from the MIT Lincoln laboratory data and MIT Lincoln laboratory are compared quantitatively.

Recent developments in the field of network communications have prompted the rise of smart grid research in the United States, China, and South Korea. RFID has become a standard technology within that domain, however many weaknesses in the security of smart grid communication still remain. In this paper we present a lightweight security protocol based on the current standard EPCGlobal Gen2. We also propose an enhanced security scheme for smart grid networks using a protocol based on the One Time Password (OPT) algorithm.

Objective Our purpose of this study is to compare insertion angles and screw lengths from Roy-Camille, Magerl, and our designed method for cervical lateral mass screw fixation in the Korean population by quantitative measurement of reformatted two dimensional (2D) computed tomography (CT) images. Methods We selected thirty Korean patients who were evaluated with thin section CT scans and reconstruction program to obtain reformatted 2D-CT images of the transversal plane passing the cranio-caudal angle using three different techniques. We measured the minimum angle to avoid vertebral artery (VA) injury, the ideal angle and depth for bicortical screwing of cervical lateral mass. Morphometric measurements of the lateral masses from C3-C7 were also taken. Results In all three techniques, the mean safety angles from the VA were less than 8 degrees and the necessary depth of the screw was about 14 mm for safety to the VA and for the bicortical purchase. In our designed technique, the mean beta angles of each level from C3 to C7 were 29.0, 29.8, 29.5, 26.3, and 23.9 degrees, respectively. Conclusion Results of this study and data from the literature indicate that differences may exist between the Korean and Western people in the length and angle for ideal lateral mass screw fixation. In addition, our technique needs further cadaveric and clinical study for safety and efficacy for being performed as alternative method for cervical lateral mass fixation.