• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.30 no.5 s.248
• /
• pp.488-495
• /
• 2006

The demand for the use of 3D CAD data over the Internet environment has been increased. However, transmission of 3D CAD data has delayed the communication effectiveness because of the CAD data size. Lightweight CAD file design methodology is required for rapid transmission in the distributed environment. In this paper, to derive lightweight CAD files from commercial CAD systems, a file translation system producing a native file is constructed first by using the InterOp and API of the ACIS kernel. Using the B-rep model and mesh data extracted from the native file, the lightweight CAD file with topological information is constructed as a binary file. Since the lightweight CAD file retains topological information, it is applied to the dimensional verification, digital mock-ups and visualization of CAD files. Effectiveness of the proposed lightweight CAD file is confirmed through various case studies.

• Journal of the Korea Computer Industry Society
• /
• v.2 no.2
• /
• pp.131-140
• /
• 2001

In this paper file transfer efficiencies of satellite and terrestrial links are analyzed, and a simulator that satellite links are supplementarily expanded to SARA(System ARchitect’ Apprentice) model, a terrestrial model of CSDN interface, is constructed. And in satellite transmission an interpretative method and a simulator of file transfer are proposed to evaluate the efficiency of file transfer. The parameters used are the message length and transmission time, and the optimum message length by transmission speed of satellite links. From the results of evaluation, in satellite transfer, it is found that when the length of message is shorter than 512 byte, the file transfer time becomes extremely long and when the length of message is set at 1,024 byte the file transfer time becomes minimum, and if the length of message is set more longer, the file transfer time abruptly increases from 2,048 byte. Therefore, from the results of file transfer simulation in the case of utilizing satellite transmission, it is found that the optimum massage length in the minimum transfer time is present closely at 1,024 byte.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.4B
• /
• pp.397-402
• /
• 2004

In this paper, we have designed and simulated a new file transmission method. This method restricts memory copy and context switching happened in traditional file transmission. This method shows an improved performance than traditional method in network environment. When the UNIX/LINUX system that uses the existing file transfer technique transmits a packet to the remote system, a memory copy between the user and kernel space occurs over twice at least. Memory copy between the user and kernel space increase a file transmission time and the number of context switching. As a result, the existing file transfer technique has a problem of deteriorating the performance of file transmission. We propose a new algorithm for solving these problems. It doesn't perform memory copy between the user and kernel space. Hence, the number of memory copy and context switching is limited to the minimum. We have modified the network related source code of LINUX kernel 2.6.0 to analyzing the performance of proposed algorithm and implement new network system calls.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.1
• /
• pp.215-223
• /
• 1997

The advantages of service in satellite links are representatively a long distance and large capacity transfer and simultaneous communication. And terrestrial links are of high speed and high quality data transfer Therefore a combined form of characteristics of satellite and terrestrial links is desirable to furnish a good quality service to subscribers. And in satellite links an analysis method and a simulation method of file transfer are conducted to evaluate the efficiency of file transfer. The parameters are used the message length and transmission time, and the number of chain record and transmission time. From the results of evaluation, in satellite links, it is found that when the message length is shorter than 512 bytes, the file transmission time becomes extremely long and when the message length is set at 1024 bytes, the file transmission time abruptly increase from 2048 bytes. Also it is confirmed that when the number of chain record is under 15, the file transmission time becomes extremely long and if the number increase up to 90,the time becomes gradually short and over 90,it becomes constant.Therefore,from the result of file transmission in th case of utilizing satelite links,it is confirmed that the optimum message length in the minmum transmission time is present closely at 1024 bytes.Also it is confirmed that when the satelite transmission sped becoms smaller from 24kbps to2400bps,the optimum message length also becomes smaller from 640 bytes to 256bytes.

• KIISE Transactions on Computing Practices
• /
• v.20 no.12
• /
• pp.632-639
• /
• 2014

In this paper, we propose a PC's self-monitoring system for protecting illegal outflow of important personal files, which are managed in the Windows environment PC. This paper is based on the idea that it should be a read (access) file operation in order to outflow files through the network. To compare the information (name, some content) obtained from all operations of the reading of the 'Windows File System Driver' and captured transmission packets of mini port of 'Windows NDIS (Network Driver Interface Specification) Driver', and, if two pieces of information match, this system will determine the transmission to user. In this paper, tentatively, we developed a function to gather file information about file read operation and developed a function for transmission packet capture. This demonstration implementation showed that the proposed process has validity and the proposed process verified that it does not significantly affect the PC's performance.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.20 no.1
• /
• pp.146-158
• /
• 2002

JPEG is good for full color representation but is poor in quality of image because of the small size and the losing compression ways. GIF is a kind of format style made for image - transmission in Compuserve which is a method of PC communication in U. S. A and now is used in world wide web owing to the efficiency of file compression and transmission. But GIF only is used 256 colors, so the images in web has a poorer quality of colors effect to be compared with those of printed catalogues. Also there can be licence problems when the images is used for commercial uses because the possession is Compuserve. The PNG is a way that the total advantages of JPEG and GIF. PNG image file is a more skillful (bitmap display unit), shows a high quality image like TIFF image about, gives superior compression , a 10% to 30% represents full color, 256 color, gray like JPEG. GIF file which uses LZW compression file is a thing which pays licence, In other hands, PNG is free from licence and more skillful image processing method against image error, and it is possible to conserve the color information. Therefore, this treatise is about how various images which are utilized for commercial printings in web, can be made into PNG files about the compression file. And the representation of image by compared the G]U images with JPEG images as well as compression file and the representation of image the superiority of color representation. In addition, 1 check out how much ranges the PNG files are available for electronic publish printing.

• Journal of Advanced Navigation Technology
• /
• v.16 no.6
• /
• pp.968-974
• /
• 2012

After launched various smart devices such as smart phone and tablet PC, people who using smart devices are provided various services. Especially, contents sharing technology is utilized in any devices. But current contents sharing systems are made on various versions for various smart devices. These methods will be raising cost for development of application. Therefore it must using web technology for reducing cost. In this paper, we had analyzed performance of file transmission using web technology and compared with application based system.

• International Journal of Internet, Broadcasting and Communication
• /
• v.11 no.2
• /
• pp.31-42
• /
• 2019

As smartphone H/W performance and mobile communication service have been enhanced, large-capacity 3D modeling files are available in smartphones. Common formats of 3D modeling files include STL (STereoLithography), OBJ (Wavefront file format specification), FBX (Filmbox), and glTF (open GL Transmission Format). Each format has different characteristics depending on the configuration and functions, and formats that are supported are varied depending on the applications. Large-size files are commonly used. The 4th generation mobile communication network secures loading of 3D modeling files and transmission of large-size geometric files in order to provide augmented reality services via smartphones. This paper explains the concepts and characteristics of major 3D file formats such as OBJ, FBX, and glTF. In addition, it compares their performance in a wired web with that in the 4th generation mobile communication network. The loading time and packet transmission in each 3D format are also measured by means of different mobile web browsers (Google Chrome and MS Edge). The experiment result shows that glTF demonstrated the most efficient performance while the loading time of OBJ was relatively excessive. Findings of this study can be utilized in selecting specific 3D file formats for rendering time reduction depending on the mobile web environments.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2018.01a
• /
• pp.133-134
• /
• 2018

본 논문에서는 네트워크상에 연결된 두 개의 단말이 클라우드나 외장형 메모리 없이 파일을 송수신할 수 있는 방법을 제안하고 이를 구현한다. 제안한 방법은 NAT로 나눠진 두 단말사이의 송수신을 위하여 TCP- Relaying 기법을 활용함으로써 데이터의 송수신을 하여 신뢰도는 높이면서 간단한 파일을 송수신할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.1C
• /
• pp.90-95
• /
• 2002

Though the FTP(File Transfer Protocol) has been used widely and stable, It has the structural weakness that can't support current file transmissions so that we have to wait the completion of previous file transmission when try to transmit another file. If try to transmit multiple files concurrently using this FTP, It has to forking multiple FTP servers and clients in each user's PC and ISP's host machine it would result in the waist of memory, resource of network and the high workload of system. In order to solving previous problem, in this paper I have designed the new model of FTP which based on multi-thread and created NFTP(Next-Generation FTP)protocol so that may reduce the workload of system and support current file transmission effectively. I have implemented NFTP and also applied to real service, as a result It have provided reliable service by reducing the workload of system and saved the waiting time which would happened.