Earticle

Sentiment Analysis is a crucial area of study within the realm of Computer Science. With the rapid advancement of Information Technology and the prevalence of social media, a substantial volume of textual comments has emerged on web platforms and social networks such as Twitter. Consequently, individuals have become increasingly active in disseminating both general and politically-related information, making it imperative to examine public responses. Many researchers have harnessed the unique features and content of social media to assess and forecast public sentiment regarding political events. This study presents an analytical investigation employing data from general discussions on Twitter to decipher public sentiment regarding the crisis in Pakistan. It involves the analysis of tweets authored by various ethnic groups and influential figures using Machine Learning techniques like the Support Vector Classifier (SVC), Decision Tree (DT), Naïve Bayes (NB) and Logistic Regression. Ultimately, a comparative assessment is conducted based on the outcomes obtained from different models in the experiments.

In this study, the mechanical joint performance of the V-Insert clamp applied to automobile exhaust pipes was evaluated through the experimental investigation of its axial load capacity. The axial load of the V-Insert clamp was also determined by using theoretical equations presented by Shoghi and compared with the experimental results. As results of the theoretical prediction, the axial load of the V-Insert clamp tended to increase along with smaller angle of the V-Insert segment and the lower friction coefficient between the V-Insert segment and exhaust pipes. The experimental results under tightening effects were similar to the theoretical results and the axial load of the V-Insert clamp presented maximum values in the range of all torques at distance of 2mm between each exhaust pipes. The experimental results under loading effects were similar to the theoretical results in the range of lower torques but deviated from the theoretical results in the range of higher torques. These results would be beneficial to improve the joint and sealing performance of the V-Insert clamp.

Weather strip is a functional component of a car body and doors for leaking protection, isolating outside noise and vibration reduction. Insert metal inserted to the weather strip plays a key role to keep the shape of the weather strip and increase its strength. Insert metal is mainly produced by a press process, which has low productivity and 40% material loss due to the scraps. To solve the problems, a high-speed rolling process for manufacturing the insert metal of weather strip is being attempted. In this study, the insert metal is manufactured by a high-speed rolling process, and its process variables: reduction, relative velocity of rollers and the number of passes, are optimized by using the FEA and the actual tests. The prototype was manufactured by the optimal process.

The wear of engine valve and seat insert is one of the most important factors which affect engine performance. Because of higher demands on performance and the increasing use of alternative fuel, engine valve and seat insert are challenged with greater wear problems than in the past. In order to solve the above problems, a simulator was developed to be able to generate and control high temperatures and various speeds during motion. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. This work focuses on the different degrees of wear at three different singular test speeds (10 Hz, 25 Hz & multi-Hz). For this study, the temperature of the outer surface of the seat insert was controlled at 350$^{\circ}C$, and the test load was 1960 N. The test cycle number was $6.0{\times}10^6$. The mean ($\pm$standard error) wear depth of the valve at 10 Hz and 25 Hz was 45.1 ($\pm$3.7)$\mu$m and 81.7 ($\pm$2.5)$\mu$m, respectively. The mean wear depth of the seat insert at 10 Hz and 25 Hz was 52.7 ($\pm$3.9)$\mu$m and 91.2 ($\pm$2.7)$\mu$m, respectively. In the case of multi-Hz it was 70.7 ($\pm$2.4)$\mu$m and 77.4 ($\pm$3.8)$\mu$m, respectively. It was found that higher speed (25 Hz) cause a greater degree of wear than lower speed (10 Hz) under identical test condition (temperature, valve displacement, cycle number and test load). In the wear mechanisms of valves, adhesive wear, shear strain and abrasive wear could be observed. Also, in the wear mechanisms of seat inserts, adhesive wear, surface fatigue wear and abrasive wear could be observed.

Face milling is required to study cutting process with a view of multipoint cutter. This experimental study mainly deals with the single and multi-insert cutting characteristics using coated tool. Because metal cutting of the single and multi-insert has a large relation to the improvement of productivity, the economic cutting process can be achieved by the analysis of proper metal cutting mechanism. Therefore, machining characteristics of face molling in this paper has been studied by investigating the role of different insert number which is concerned with mean cutting force, the RMS values of AE(acoustic emission) signal, tool life and surface roughness in milling SS 41 and SUS 304. The cutting force and AE signal are monitored to make an analysis of cutting process. The surface roughness of the specimens machined by inserts of different numbers is measured at different speeds, feeds and depth of cut. The width of flank wear is also observed.

In the present study, a numerical investigation of an insert injection molding process was carried out for the development of thermoplastic microfluidic chip plates with metal electrodes. Insert injection molding technology enables efficient realization of a plastic-metal hybrid structure and various efforts have been undertaken to produce novel components in several application fields. The microfluidic chip with metal inserts was proposed as a representative example and its molding process was analyzed. The important characteristics of the filling stage, such as the effects of filling time and thickness of the part cavity, were characterized. Furthermore, the detailed distributions of pressure and temperature at the end of the filling stage were investigated, revealing the significance of metal insert temperature.

Textile machinery affects various industry, such as sport leisure industry, metal and chemistry material, electric electron, mechanical energy, packing and printing industry. In case of design of textile machine, the very important fact is absorbing the minute vibration induced by spinning thread and insert which is the part of spindle plays a role of reduction of impact caused by oscillation of thread bobbin. Therefore, Optimal design was executed by design of experiments and kriging optimal design methods to prevent fracture of spindle insert under the fatigue condition and deduced the best value of design parameter to improve the stability of the products. The highest sensitivity is showed at the design parameter A and D. As the spiral number of insert is increase, tension force applied its edge is distributed at whole model and the stress concentration is reduced.

The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The shrink fit analysis has been performed that enables optimal design of the dies taking into account the elastic deflections which generated in shrink fitting the die inserts and that caused by the stresses generated in the process and by using DEFORM software for process analysis. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the die design. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.

A milling process with 45 degree chamfered inserts produces a perfect flat surface only in theory. It is due to many unwanted factors including thermal effect, dynamic effect, the problem of the controller used and the problem of accuracy of the machine tool. In this study, introduced is a method to improve the surface roughness by redesigning of the chamfer angle of the insert, which traditionally has been 45 degree. First, the relationship between the fixed machine coordinate and the relative coordinate on the insert is derived. This transfer matrix is used to determine the new insert angle to maximize the flatness of the machined surface. A newly designed insert is manufactured, and used to carry out the experiment. It is proved that she insert designed by the proposed method produced a much flatter surface than a traditional one.

스마트팩토리의 구축을 위해서는 제조환경에서 여러 센서 및 기기 등을 연결하여 데이터를 수집하고, 데이터 분석을 통해 생산설비 등의 장애를 진단하거나 예측하여야 한다. 본 논문에서는 공작기계에서 제품을 가공하기 위해 사용되는 절삭용 인서트의 잔여 유효 수명을 예측하기 위해 진동 신호를 기반으로 한 가중화 k-최근접이웃(Weighted k-NN) 알고리즘, 의사결정나무(Decision Tree), 서포트벡터회귀(SVM), XGBoost, 랜덤포레스트(Random forest), 1차원 합성곱신경망(1D-CNN), 그리고 진동 신호를 FFT한 주파수 스펙트럼에 대해 알아보았다. 연구결과, 주파수 스펙트럼으로는 잔여 유효수명의 정확한 예측에 대해서는 신빙성있는 기준을 제공하지 못한다는 것을 알수 있었고, 예측 모델 중 가중화 k-최근접이웃 알고리즘이 MAE가 0.0013, MSE가 0.004, RMSE가 0.0192로 가장 우수한 성능을 나타내었다. 이는 가중화 k-최근접이웃 알고리즘에 의해 예측되는 인서트의 잔여 유효 수명의 오차가 0.001초 수준으로 평가되어, 실제 산업현장에 적용이 가능한 수준으로 사료된다.

For the implementation of a smart factory, it is necessary to collect data by connecting various sensors and devices in the manufacturing environment and to diagnose or predict failures in production facilities through data analysis. In this paper, to predict the residual useful lifetime of milling insert used for machining products in CNC machine, weight k-NN algorithm, Decision Tree, SVR, XGBoost, Random forest, 1D-CNN, and frequency spectrum based on vibration signal are investigated. As the results of the paper, the frequency spectrum does not provide a reliable criterion for an accurate prediction of the residual useful lifetime of an insert. And the weighted k-nearest neighbor algorithm performed best with an MAE of 0.0013, MSE of 0.004, and RMSE of 0.0192. This is an error of 0.001 seconds of the remaining useful lifetime of the insert predicted by the weighted-nearest neighbor algorithm, and it is considered to be a level that can be applied to actual industrial sites.

The wear on engine valve and seat insert is one of the most important factors affecting engine performance. The engine valve and seat insert must be able to withstand the severe environment that is created by: high temperature exhaust gases generated while the engine is running, rapid movement of the valve spring, high pressure generated in the explosive process. In order to study such problems, a simulator has been developed to generate and control high temperatures and various speeds during motion. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. This work focused on the test of various degrees of wear on four different exhaust valve materials such as HRV40, HRV40-FNV (face nitrided valve), STL #32, STL #6,. Throughout all tests performed in this study, the outer surface temperature of the seat insert was controlled at $350^{\circ}C$, the cycle number was $4.0{\times}10^6$, the test load was 6860 N, the fuel was LPG the test speed was 20 Hz (2400 RPM) and the seat insert material was HVS1-2. The mean (standard deviation) maximum roughness of the exhaust valve and seat insert was $25.44\;(3.16)\;{\mu}m$ and $27.53\;(3.60)\;{\mu}m$ at the HRV40, $21.58\;(2.38)\;{\mu}m$ and $25.94\;(3.07)\;{\mu}m$ at the HRV40-FNV, $36.73\;(8.98)\;{\mu}m$ and $61.38\;(7.84)\;{\mu}m$ at the STL #32, $73.64\;(23.80)\;{\mu}m$ and $60.80\;(13.49)\;{\mu}m$ at the STL #6, respectively. It was discovered that the maximum roughness of exhaust valve was lower as the high temperature hardness of the valve material was higher under the same test conditions such as temperature, test speed, cycle number, test load and seat insert material. The set of the HRV40-FNV exhaust valve and the HVS1-2 seat insert showed the best wear resistance.

폭발물탐지장비의 개발, 시험, 점검 등을 안전하게 수행하기 위해서는 비활성 모의 폭발물의 사용이 현장에서 강하게 요구된다. 본 연구는 해외 기술에만 의존하던 비활성 모의 폭발물 제작기술을 국내에 자체 확보함으로써 우리나라 보안 장비 산업 발전에 이바지하고자 수행되었다. 연구목적을 달성하기 위해, TNT, C4, ANFO 3종에 대한 비활성 모의 폭발물을 설탕을 기반으로 제작하였고, 현장 적용 가능성을 확인하기 위해 실제 폭발물 및 상용 비활성 모의 폭발물과 비교를 통해 통계적으로 검증하였다. 연구분석방법으로 CT X-Ray 검색장비를 이용하여 제작된 비활성 모의 폭발물이 실제 폭발물로 인식되는지 확인하였고, 2D X-ray 검색장비를 통해 유효원자번호를 측정하였다. 이후 측정된 유효원자번호 값을 통계적 기법을 활용하여 기준물질과 비교하였다. 연구결과, 제작된 비활성 모의 폭발물 3종은 CT X-Ray 검색 장비에서 실제 폭발물로 인식되었으며, 2D X-ray 검색장비에서 약 6.75에서 6.90 사이의 유효원자번호를 나타냈다. 독립표본 T-test와 분산분석에서는 기준물질들과 유의수준 5%에서 통계적으로 차이가 없는 것으로 나타났다. 더하여, Levene Test을 통해 제작된 비활성 모의 폭발물의 품질이 기준물질과 비교하여 균일하거나 상대적으로 더 좋다는 결과를 얻을 수 있었다. 이 연구결과는 국내 보안 장비 산업의 자립성과 신뢰성 확보에 기여할 수 있으며, 향후 다양한 모의 물질 제작 및 탐지 알고리즘 테스트 분야로의 확장도 기대된다.

This study was conducted to contribute to the development of Korea's security equipment industry by securing its own production technology for inactive simulated explosives in Korea, which relied only on overseas technology. In order to achieve the research objectives, inactive simulated explosives for three types of TNT, C4, and ANFO were produced based on sugar and statistically verified through comparison with actual explosives and commercial inactive simulated explosives to confirm the applicability in the field. As a research analysis method, it was confirmed whether the inactive simulated explosives manufactured using the CT X-Ray search equipment were recognized as actual explosives, and the effective atomic number was measured through the 2D X-ray search equipment. Then, the measured effective atomic number value was compared with the reference substance using a statistical technique. As a result of the study, the three types of inactive simulated explosives were recognized as actual explosives in the CT X-Ray search equipment and indicated effective atomic numbers between 6.75 and 6.90 in the 2D X-ray search equipment. In the independent sample T-test and variance analysis, there was no statistical difference from the reference substances at a significance level of 5%. In addition, it was possible to obtain a result that the quality of the inert simulated explosives manufactured through the Levene Test was uniform or relatively better compared to the reference material.

In this study, simulation studies were conducted to develop insert injection molds to improve the mass production of terminal assemblies. For the main part of the automobile door latch, charging, holding pressure and deformation analysis were performed according to the gate position of the injection process. As a result of injection molding analysis of the terminal assembly, the flow pattern was uniformly made while maintaining a constant balance of the filling of the product, and the pressure distribution at the time of filling was confirmed. When the analysis results are applied to the mold fabrication in the improved structural method, the transfer lines of the molten resin are controlled by the dam of the 1st injection molding, so that the transmission line is not short-circuited or deformed, and the watertightness, corrosion resistance, and good surface We believe the injection will be possible.

Tool tips of the circular saw for the steel cutting have commonly applied to brazing type welded the saw body to tips. In this case, when the tool tip is required to the exchange, many problems were occurred as the exchange cost is high and its time is long. In this study, to resolve the brazing type circular saw, the insert type circular saw has designed and made. Also, to confirm the performance of new type circular saw, the various experiments were carried out under condition of tip's shape and machining conditions.

The critical current of the HTS(High Temperature Superconductor) tape is governed by cooling temperature, magnetic field and its angle to HTS tape originated from its geometrical structure. At the HTS coil design stage, the critical current of the coil is calculated by considering the Ic-B characteristics of the 2G tape and the operating current is determined based on the critical current. The operating current and the structure of the 5 T coil are suggested through the FEM (Finite Elements Method) analysis and calculation. As a part of our on-going research on a 20 T LTS/HTS magnet, we have designed and constructed a 5 T HTS insert coil and tested it in liquid helium temperature.

본 연구는 IPTV 광고효과에 영향을 미치는 요인이 무엇인가를 알아보기 위해 이루어졌다. 연구결과 첫째, 양방향성 메시지를 담고 있는 IPTV 특성반영 광고가 일반 TV 광고보다 광고주목율과 광고태도가 긍정적으로 나타났다. 둘째, 양방향성 메시지를 담고 있는 IPTV형 광고의 경우 제품상세 정보를 제시하는 조건이 효과적인 것으로 나타났다. 셋째, 양방향성 메시지 표현중 플로팅 표현전략 효과가 가장 높게 나타났다. 넷째, 매체 수용자의 혁신성 특성은 IPTV에 관한 지식수준과 추가 정보 탐색의도에 영향을 미치는 것으로 나타났다. 본 연구결과는 IPTV 사업자들에게 양방향성 메시지를 탑재 하는 것이 효과적이라는 이론적 근거를 제시해 줄 뿐 아니라 플로팅 표현전략이 광고의 클릭의도를 높일 수 있는 방안이라는 것을 시사한다.

The purpose of this study was to explore the effect of the interactive message expression and consumer characteristic insert IPTV advertising. The results of this study were follow: Firstly, Attention and attitude of interactive message advertising appeared than general TV advertising so that it was high. Second, In case of interactive message advertising, It appeared efficiently than the advertising without the advertisement detail information which is putting the good detail information. Third, In interactive message expression of IPTV advertising, Floating expression strategy appeared efficiently most. Lastly, Adoption of consumer characteristic was revealed that we had an influence on the knowledge level and the information search intention about IPTV. We present theoretical basis which to present interactive message to IPTV supplier is efficient, and the plan which floating expression can make the click intention of the advertising.

Residual stress is an important factor in machining process an attempt has been made to analyze the residual stress in turning of AISI4340 steel. The residual stresses that can be found in a cutting tool insert are mainly generated at the final step of the machining process. Feed, speed, depth of cut are the input parameter. The residual and the tool wear are the output responses. Cryogenic treatment will improve the performance and made significant of wear resistance, better residual stress and product quality of cutting tool. This is the study of review the literature from performance of cryogenically treated cutting tool insert in varying nose radius and the soaking period. The level of the generated residual stress depends on the machine materials and on the process parameters used. The overall goal of the present paper is to identify an analytical relationship between residual stress and turning process parameters accounting also for the material being machined.

Two-phase thermosyphons are devices that can transfer large amounts of heat flux with the boiling and condensation of the working fluid resulting from small temperature differences. A two-phase thermosyphon consists of the evaporators, an insulation unit, and the condensers. The working fluid inside the evaporator is evaporated by the heating of the evaporator in the lower part of the two-phase thermosyphon and the evaporated steam rises to the in the upper part to transfer heat in response to the cooling fluid outside the tube. The resultant condensed working fluid flows downward along the inside surface of the tube due to gravity. The resultant condensed working fluid flows downward along the inside surface of the tube due to gravity. These processes form a cycle. In the present study, condensers with various insert devices of a loop type two-phase thermosyphon which is 480mm wide, 68mm long, and 1,000mm high was used. The heat transfer pipes in the loop type two-phase thermosyphon were 15mm in diameter and 1,000mm in length and 98 heat transfer pipes were installed in loop type two-phase thermosyphon. The inside of the condensers with various insert devices was composed of heat transfer pipes installed to increase the heat transfer surface area of the heating media in the heat transfer pipes condensers with various insert devices. Using refrigerant R134a as a working fluid for the loop type two-phase thermosyphon to conduct heat transfer performance experiments for changes in the temperature of the cooling air outside the condenser and changes in the mass flow rate. According to the results of the present experiments, as the spaces between internal discontinuous pins decreased, pressure drops increased. Changes in the temperatures at the outlet of the condenser were shown to be a little smaller. Therefore, it can be seen that as the spaces between internal discontinuous pins decreased, the heat transfer performance increased. As the temperature of the air flowing in the condenser with various insert devices increased, the condensation heat transfer rate of the thermosyphon increased. As the condenser with various insert devices refrigerant inflow temperature increased, the condensation heat transfer rate of the condensers with various insert devices of the thermosyphon heat exchanger increased.