• The Mathematical Education
• /
• v.63 no.2
• /
• pp.233-254
• /
• 2024

This paper delves into the symbiotic integration of coding and mathematics education, aimed at cultivating computational thinking and enriching mathematical problem-solving proficiencies. We have identified a corpus of scholarly articles (n=38) disseminated within the preceding two decades, subsequently culling a portion thereof, ultimately engendering a contemplative analysis of the extant remnants. In a swiftly evolving society driven by the Fourth Industrial Revolution and the ascendancy of Artificial Intelligence (AI), understanding the synergy between these domains has become paramount. Mathematics education stands at the crossroads of this transformation, witnessing a profound influence of AI. This paper explores the evolving landscape of mathematical cognition propelled by AI, accentuating how AI empowers advanced analytical and problem-solving capabilities, particularly in the realm of big data-driven scenarios. Given this shifting paradigm, it becomes imperative to investigate and assess AI's impact on mathematics education, a pivotal endeavor in forging an education system aligned with the future. The symbiosis of AI and human cognition doesn't merely amplify AI-centric thinking but also fosters personalized cognitive processes by facilitating interaction with AI and encouraging critical contemplation of AI's algorithmic underpinnings. This necessitates a broader conception of educational tools, encompassing AI as a catalyst for mathematical cognition, transcending conventional linguistic and symbolic instruments.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.6
• /
• pp.876-888
• /
• 1986

The Study is concerned with the analysis of unconstrained axisymmetric piercing as a nonsteady forging process by the rigid-plastic finite element method. In the numerical analysis of axisymmetric piercing, the initial velocity field is generated by assuming the material as a linear viscous material to begin with in order to facilitate the input handling and to ensure better convergencey. The strain-hardening effect for nonsteady deformation and the friction of the die-material interial interface are considered in the formulation. Rigid body treatment is also incorporated in the developed program. The experiments are carried out for aluminum alloy specimens (A1204) with different specimen heights. It is shown that the experimental results are in excellent agreement with the finite element simulations is deformed configuration. For load prediction the theoretical prediction shows excellent agreement with th eexperimental laod in the initial stage of loading before fracture of the specimen is not initiated. Distribution of stresses, strains and strain rates has been found for the given cases in computation. On this basis several fracture criteria are introduced in order to check the fracture initiation. It is found that maximum shear criterion is capable of good fracture prediciton.

• Journal of Computational Design and Engineering
• /
• v.1 no.1
• /
• pp.27-36
• /
• 2014

Similar to the essential components of many mechanical systems, the geometrical properties of the teeth of spiral bevel gears greatly influence the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show a unique advantage in transmission due to their constant spiral angle property. However, a mathematical model suitable for accurate digital modeling, differential geometrical characteristics, and related contact analysis methods for tooth surfaces have not been deeply investigated, since such gears are not convenient in traditional cutting manufacturing in the gear industry. Accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed in this study, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry; actually, the tooth surface is a parametric surface defined on a parallelogrammic domain. Equivalence proof of the tooth surface geometry is then given in order to greatly simplify the mathematical model. As major factors affecting the lubrication, surface fatigue, contact stress, wear, and manufacturability of gear teeth, the differential geometrical characteristics of the tooth surface are summarized using classical fundamental forms. By using the geometrical properties mentioned, manufacturability (and its limitation in logarithmic spiral bevel gears) is analyzed using precision forging and multiaxis freeform milling, rather than classical cradle-type machine tool based milling or hobbing. Geometry and manufacturability analysis results show that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multiaxis freeform milling also need to be solved in a further study.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.5
• /
• pp.50-56
• /
• 2014

A technique based on the finite element method (FEM) is used in the simulation of metal cutting process. This offers the advantages of the prediction of the cutting force, the stresses, the temperature, the tool wear, and optimization of the cutting condition, the tool shape and the residual stress of the surface. However, the accuracy and reliability of prediction depend on the flow stress of the workpiece. There are various models which describe the relationship between the flow stress and the strain. The Johnson-Cook model is a well-known material model capable of doing this. Low-alloy steel is developed for a dry storage container for used nuclear fuel. Related to this, a process analysis of the plastic machining capability is necessary. For a plastic processing analysis of machining or forging, there are five parameters that must be input into the Johnson-Cook model in this paper. These are (1) the determination of the strain-hardening modulus and the strain hardening exponent through a room-temperature tensile test, (2) the determination of the thermal softening exponent through a high-temperature tensile test, (3) the determination of the cutting forces through an orthogonal cutting test at various cutting speeds, (4) the determination of the strain-rate hardening modulus comparing the orthogonal cutting test results with FEM results. (5) Finally, to validate the Johnson-Cook material parameters, a comparison of the room-temperature tensile test result with a quasi-static simulation using LS-Dyna is necessary.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.7
• /
• pp.4375-4380
• /
• 2015

This study was performed to evaluate a newly proposed heating process of blank, which was used for Crank throw in the diesel engine, and provide design guidelines of heating processes. Non-linear numerical analyses were done using ANSYS program to investigate temperature and thermal stress distributions of blank during heating processes. The heating process consists of two stages; one is a heating stage with 20 hours, and the other is a holding stage with 12 hours, totaling 32-hour heating time. Based on analysis results, it was found that the temperature difference between the center and the surface of blank increased linearly during the heating stage but decreased gradually during the holding stage of heating processes, while max. equivalent stress, $12.5kg/mm^2$, was found at the center of blank after 10-hour heating time. As the guideline of blank heating process, it was recommended to keep the temperature difference between the center and the surface of blank to be within $150^{\circ}C$ when the environment temperature in furnace reaches $650^{\circ}C$ during a heating stage.

• Journal of Conservation Science
• /
• v.31 no.4
• /
• pp.489-497
• /
• 2015

Iron sickle is tool used in various ways and have various form. It has agricultural feature as well as is used in weapon. Previous studies have been focused on features of farming tools. In this study, metallurgical analysis of iron sickles are introduced because examples of analysis for iron sickles is rare. Two sickles form Yeongi Jangjae-ri are investigated and compared to one sickle of Yeongi Songwon-ri. Three sickles have forging molding process and heat treatment process. No.1 sickle of Jangjae-ri have martensite of quenching. No.2 sickle of Jangjae-ri was undergone high temperature as compared with others. This show manufacturing technology of sickles from Jangjae-ri in over the Songwon-ri's.

• Korean Journal of Heritage: History & Science
• /
• v.35
• /
• pp.138-158
• /
• 2002

To compare and analyze technical system related to manufacturing of ironware during the period of the Three Kingdoms, an analysis was conducted on the minute system of metalwork, as study objects, of the remains of the Mt. Wolpyeong fortress wall in Daejeon in the period of capital during the era of the Three Kingdoms in the 5th century, the Sanwol-ri remains in the 6th century in Gunsan and the remains of ironware excavated from the great ancient tomb of Hwangnam of the Silla dynasty in the 5th century. The result of analysis shows that in the most of the casting products, the minute system of white cast iron were contained. While the iron part of decarbonization was in the system by casting as white cast iron in the central part, on the surface layer it was turned out that comparatively uniform 100% pearlite system of about 1~2mm degree was existing. The part of pearlite on the surface layer was caused by decarbonization, which appears in all the parts of blade front end and handle. Therefore, it was found that the iron part of decarbonization was manufactured by casting, and then was processed at the high temperature by decarbonization. For the products of forging, after processing the products on the basis of pure iron for materials, they manufactured the ironware that raises the strength by carbonizing that keeps carbon infiltrated on the necessary part, by the method of black smith welding that add pure iron to steel, or by varying the method of heat processing onto the part required of strength. Though limited, we could understand that the technical systems for manufacturing skill of ironware in the areas of Baekje and Silla were different each other. In the technical system for Hwangnam great ancient tomb in the Silla area, it is found that they had raised the strength on the necessary part by applying the steelmaking method of carbonizing in the last stage of production of products, in the meantime in Baekje area, it appears that they had produced steel in advance in the first stage of production of the products, and used the produced steel only to the necessary part.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.699-704
• /
• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. New the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some deflects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical terming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions fur forming a long-neck flange are simulated by FE analyses with a commercial cede DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion fur forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any deflects.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.9
• /
• pp.1043-1048
• /
• 2014

As micro screws feature reduced screw lengths and pitches, the resulting clamping force diminishes because of the reduced length of the actual joints. The elements of the clamping force are material, geometry, and friction. We studied the shrinking size of the screw and the methods to improve the clamping force by changing the material. We developed a micro screw using SWCH18A and SUS XM7 materials, and obtained the precision and thickness of the pitch through three-dimensional measurement. We also measured the external resistance of the micro screw by applying the Vicker's hardness test and conducted a break surface analysis using a break torque test and SEM for obtaining the break characteristics.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.8
• /
• pp.212-219
• /
• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. Now the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some defects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical forming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions for forming a long-neck flange are simulated by FE analyses with a commercial code DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion for forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any defects.