• Transactions of Materials Processing
• /
• v.27 no.4
• /
• pp.250-256
• /
• 2018

Oxygen-free copper (OFC) was prepared as a 90 mm cube and then processed with Multi-Axial Diagonal Forging - Initialization of Prior manufacturing History (MADF). The MADF process has been newly developed as a severe plastic deformation method. The MADF process consists of upset forging with a thickness reduction of 30% and diagonal forging with a diagonal angle of $135^{\circ}$. 1 cycle process consists of a 12 passes forging process. In order to analyze the characteristic changes according to the number of iterations, 1, 2, and 3 cycles of the MADF process were performed. The OFC specimens were MADF processed without surface cracks up to 3 cycles. The microstructure, hardness and tensile test of processed materials were analyzed to study the change of material properties according to the amount of MADF process. The results showed that the MADF process effectively refined the microstructure and increased the strength of OFC. In the case of specimens processed for more than 2 cycles, the grains of all measurement regions were refined to be less than $7{\mu}m$ of grain size. The 1 cycle MADF processed OFC showed the highest mechanical properties with the hardness of 132 HV and tensile strength of 395 MPa. Hardness and strength seemed to be saturated when processed over 2 cycles.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.46 no.1
• /
• pp.103-111
• /
• 2009

In SCA, the core framework must include the domain parser to parse the domain profile and thus reconstructs the platform on the time including the starting of the platform, the initialization of the new radio, and etc. The domain profile is described in XML and it includes the characteristics about the software component or the hardware device in a platform. Elementarily, the core framework has to have within the domain profile parser in order to parse the domain profile. In this paper, in order to apply to the limited environment like the mobile terminal, we propose the method for reducing the size of the domain profile parser and for strengthening the independency of the XML parser vendor to have with the domain profile parser. Therefore, domain profile parser can be solve the problem like the overhead about the DOM tree creation due to the repetitive parsing of the domain profile, the compatibility degradation by the specific XML parser vender, the dependency about the domain profile technique, and etc.

• Journal of KIISE:Computing Practices and Letters
• /
• v.9 no.6
• /
• pp.712-717
• /
• 2003

A novel multi-snake is proposed for efficient extraction of multi-object contours from a natural scene. An NTGST(noise-tolerant generalized symmetry transform) is used as a context-free attention operator to detect and locate multiple objects from a complex background and then the snake points are automatically initialized nearby the contour of each detected object using symmetry map of the NTGST before multiple snakes are introduced. These procedures solve the knotty subjects of automatic snake initialization and simultaneous extraction of multi-object contours in conventional snake algorithms. Because the snake points are initialized nearby the actual contour of each object, as close as possible, contours with high convexity and/or concavity can be easily extracted. The experimental results show that the proposed method can efficiently extract multi-object contours from a noisy and complex background of natural scenes.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.16 no.1
• /
• pp.41-54
• /
• 2020

In this paper, it will study various problems such as personal information infringement from when using various useful Apps in the Smartphone environment. It also researched the vulnerabilities Mobile Apps and the risks of personal information leakage when using Smartphone information to decrease threat and find solution. In the second chapter, it will check the existing Mobile App related Apps. In the third chapter, it will check the threats and major factors that caused by the leakage of personal information which related to the app. Then it will suggest solution and end with conclusion. This paper also looked at various problems that caused by illegal adverse effect from illegal personal information collection. Then it researched and made suggestion to make consideration on safety of personal information and privacy infringement that threat to personal information For safety of mobile banking, it proposed a safety method to separate and manage the code which has the core logic which required to run the App. For safety of direction App, when running the direction App, even if the information is collected, location information for unauthorized accessed will encrypt and store in DB, so that access to personal information is difficult. For delivery App environment, by using the national deliver order call center's representative phone to receive a telephone order then, the customer information is delivered to the branch office when it receive order and it will automatically delete information from the server when the delivery is completed by improving DB server of order. For the smart work app environment, the security solution operates automatically by separating and make independent private and work areas. Then it will suggest initialization for company's confidential business information and personal information to safe from danger even if loss.

• Journal of KIISE
• /
• v.43 no.7
• /
• pp.827-833
• /
• 2016

HTTP Adaptive Streaming (HAS) is a technique that adapts its video quality to network conditions for providing Quality of Experience. In the HAS approach, a video content is encoded at multiple bitrates and the encoded video content is divided into several video segments. A HAS player estimates the network bandwidth and adjusts the video bitrate based on estimated bandwidth. However, the segment scheduler in the conventional HAS player requests video segments periodically without considering TCP. If the waiting duration for the next segment request is quite long, the TCP connection can be initialized and it restarts slow-start. Slow-start causes the reduction in TCP throughput and consequentially leads to low-quality video streaming. In this study, we propose a TCP-aware segment scheduling scheme to improve performance of HAS service. The proposed scheme adjusts request time for the next video request to prevent initialization of TCP connection and also considers the point of scheduling time. The simulation proves that our scheme improves the Quality of Service of the HAS service without buffer underflow issue.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.7
• /
• pp.1318-1324
• /
• 2007

TSP(Traveling Salesman Problem) is a problem finding out the shortest distance out of many courses where given cities of the number of N, one starts a certain city and turns back to a starting city, visiting every city only once. As the number of cities having visited increases, the calculation rate increases geometrically. This problem makes TSP classified in NP-Hard Problem and genetic algorithm is used representatively. To obtain a better result in TSP, various operators have been developed and studied. This paper suggests new method of population initialization and of sequential transformation, and then proves the improvement of capability by comparing them with existing methods.

• Journal of Advanced Navigation Technology
• /
• v.23 no.2
• /
• pp.186-193
• /
• 2019

This paper presents and implements a simple programmable PCM encoder structure uisng the commutation method. In the telemetry system, information is required to assign each data to the channel in order to generate a frame format the data acpuired from the sensor. In this case, when the number of state information is large or the data type is various, there is a necessity to input a large amount of information to each channel. However, the more the number of channels and data, the more probability the error will occur. Therefore, in this paper, the channel information is created using the program. And PCM encoder was implemented to store channel information in ROM. The proposed PCM encoder architecture reduces the likelihood of errors. And it can improve the development speed. The validity of proposed structure is proved by simulation.

• International Journal of Computer Science & Network Security
• /
• v.21 no.1
• /
• pp.143-151
• /
• 2021

The enormous prevalence of transferring official confidential digital documents via the Internet shows the urgent need to deliver confidential messages to the recipient without letting any unauthorized person to know contents of the secret messages or detect there existence . Several Steganography techniques such as the least significant Bit (LSB), Secure Cover Selection (SCS), Discrete Cosine Transform (DCT) and Palette Based (PB) were applied to prevent any intruder from analyzing and getting the secret transferred message. The utilized steganography methods should defiance the challenges of Steganalysis techniques in term of analysis and detection. This paper presents a novel and robust framework for color image steganography that combines Linear Congruential Generator (LCG), simulated annealing (SA), Cesar cryptography and LSB substitution method in one system in order to reduce the objection of Steganalysis and deliver data securely to their destination. SA with the support of LCG finds out the optimal minimum sniffing path inside a cover color image (RGB) then the confidential message will be encrypt and embedded within the RGB image path as a host medium by using Cesar and LSB procedures. Embedding and extraction processes of secret message require a common knowledge between sender and receiver; that knowledge are represented by SA initialization parameters, LCG seed, Cesar key agreement and secret message length. Steganalysis intruder will not understand or detect the secret message inside the host image without the correct knowledge about the manipulation process. The constructed system satisfies the main requirements of image steganography in term of robustness against confidential message extraction, high quality visual appearance, little mean square error (MSE) and high peak signal noise ratio (PSNR).

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.4
• /
• pp.183-188
• /
• 2023

Game object inheritance and multiple components allow for visualization of system architecture, good code reuse, and fast prototyping. On the other hand, objects are more likely to rely on high latency between game objects and components, static casts, and lots of references to things like null pointers. Therefore, It is important to design a game in such a way so that the dependency of objects on multiple classes could be reduced and existing codes could be reused. Therefore, we designed the game to make the classes more modular by applying Dependency Injection and the design patterns proposed by the Gang of Four. Since these dependencies are attributes of the game object and the injection occurs only in the initialization pass, there is little performance degradation or performance penalty in the game loop. Therefore, this paper proposed an efficient design method to effectively reuse APIs in the design and implementation of survival games.

• Composites Research
• /
• v.21 no.1
• /
• pp.30-39
• /
• 2008

In this paper, a parallel micro genetic algorithm was utilized in the optimal design of composite structures instead of a conventional genetic algorithm(SGA). Micro genetic algorithm searches the optimal design variables with only 5 individuals. The diversities from the nominal convergence and the re-initialization processes make micro genetic algorithm to find out the optimums with such a small population size. Two different composite structure optimization problems were proposed to confirm the efficiency of micro genetic algorithm compared with SGA. The results showed that micro genetic algorithm can get the solutions of the same level of SGA while reducing the calculation costs up to 70% of SGA. The composite laminated structure optimization under the load uncertainty was conducted using micro genetic algorithm. The result revealed that the design variables regarding the load uncertainty are less sensitive to load variation than that of fixed applied load. From the above-mentioned results, we confirmed micro genetic algorithm as a optimization method of composite structures is efficient.