• Journal of Digital Convergence
• /
• v.13 no.7
• /
• pp.23-31
• /
• 2015

With the expiration of main patent of printing method, public interest now has shifted to 3D printing. In this, it needs to shine a light on the negative effects, particularly in the socio-economic aspect of 3D printing. By analyzing the existing research findings, policy reports and press releases, the negative effects of 3D printing and its countermeasures were derived. The main drawbacks of 3D printing includes the following: It might cause 3D printing-related crimes(e.g. printed weapons, intellectual property infringement, etc.) and it poses a big threat to other related business sectors.(e.g. potential job loss in molding and medical equipments manufacturing industries) What's more, the nature of 3D printing that it is easy to operate attracts lots of people, which then leads to serious social and environmental problems-product liability, ethical issues, environmental pollution, and finally government's blindly excessive investment in 3D printing. To avoid such potential risks, the government should establish and enforce the institutional law, and guidelines. Government's rational investment decision is also inevitable for the short-term and long-term sustainability of 3D printing.

• Journal of the Korean Society for information Management
• /
• v.28 no.3
• /
• pp.103-121
• /
• 2011

This study is to seek to apply resource types of RDA to KCR4. It is difficult to choose appropriate term and to embody FRBR model because GMD of KCR4 is the mixture of content-based vocabularies and carrier-based vocabularies. SMD is to need to reflect the current technological terms. Resource type of RDA was already developed to overcome limitation of AACR2's GMD, and would affect the world cataloging environment, therefore it is need to apply resource type of RDA to Korean cataloging rule. For this study, case study and survey were used. In case study, it was to scan all GMD term for one university library to build by programming and to grape librarian and users' potential need. In the survey by cataloging librarian, it was to figure out the current description of resource type in university library and to test RDA resource type. As a result, it was needed to revise the vocabulary to the obvious and user-understandable list. Also it was different in correction rate in RDA testing by resource type. Based on the case study and the survey, RDA resource type was applied to KCR4 resource list by adding term such as computer game in content type, and by inserting terms such as DVD, CD-ROM, Blu-Ray, computer file in carrier type. It also applied RDA description method and display means to KCR4. This study would apply RDA resource type to KCR4 and contribute to revise KCR4 resource type.

• Journal of the Institute of Electronics Engineers of Korea CI
• /
• v.39 no.6
• /
• pp.53-67
• /
• 2002

The multimedia synchronization is one of the key issues to be resolved in order to provide a good quality of multimedia related services, such as Video on Demands(VoD), Lecture on Demands(LoD), and tele-conferences. In this paper, we introduce an adaptive multimedia synchronization algorithm using the level of buffers and load of servers, which are modeled and analyzed by ExSpect, a Petri net based simulation tool. In the proposed algorithm, the audio and video buffers are divided to 5 different levels, and the pre-defined play-out speed controller tries to make the buffer level to be normal in different temporal relations between multimedia streams using buffer levels and server loads. Because each multimedia packet is played by the pre-defined play-out speed, the media data can be reproduced within the permissible limit of errors while preserving the level of buffers to be normal. The proposed algorithm is able to handle and support various communication restrictions between providers and users, and offers little jitter play-out to many users in networks with the limited transmission capability. The performance of the developed algorithm is analyzed in various network conditions using a Petri net simulation tool.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.47 no.8
• /
• pp.56-63
• /
• 2010

This work proposes a 12b 100MS/s 0.13um CMOS pipeline ADC for battery-powered mobile video applications such as DVB-Handheld (DVB-H), DVB-Terrestrial (DVB-T), Satellite DMB (SDMB), and Terrestrial DMB (TDMB) requiring high resolution, low power, and small size at high speed. The proposed ADC employs a three-step pipeline architecture to optimize power consumption and chip area at the target resolution and sampling rate. A single shared and switched op-amp for two MDACs removes a memory effect and a switching time delay, resulting in a fast signal settling. A two-step reference selection scheme for the last-stage 6b FLASH ADC reduces power consumption and chip area by 50%. The prototype ADC in a 0.13um 1P7M CMOS technology demonstrates a measured DNL and INL within 0.40LSB and 1.79LSB, respectively. The ADC shows a maximum SNDR of 60.0dB and a maximum SFDR of 72.4dB at 100MS/s, respectively. The ADC with an active die area of 0.92 $mm^2$ consumes 24mW at 1.0V and 100MS/s. The FOM, power/($f_s{\times}2^{ENOB}$), of 0.29pJ/conv. is the lowest of ever reported 12b 100MS/s ADCs.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.5
• /
• pp.796-805
• /
• 2000

A 30GHz band low noise amplifier module, which has linear gain of 30dB and noise figure of 2.6dB, for 30GHz satellite communication transponder was developed by use of MMIC and thin film MIC technologies. Two kinds of MMIC circuits were used for the low noise amplifier module, the first one is ultra low noise MMIC circuit and the other is wideband and high gain MMIC circuit. The pHEMT technology with 0.15$mu extrm{m}$ of gate length was applied for MMIC fabrication. Thin film microstrip lines on alumina substrate were used to interconnect two MMIC chips, and the thick film bias circuit board were developed to provide the stabilized DC bias. The input interface of the low noise amplifier module was designed with waveguide type to receive the signal from antenna directly, and the output port was adopted with K-type coaxial connector for interface with the frequency converter module behind the low noise amplifier module. Space qualified manufacturing processes were applied to manufacture and assemble the low noise amplifier module, and space qualification level of environment tests including thermal and vibration test were performed for it. The developed low noise amplifier was measured to show 30dB of minimum gain, $\pm$0.3dB of gain flatness, and 2.6dB of maximum noise figure over the desired operating frequency range from 30 to 31 GHz.

• Journal of IKEEE
• /
• v.5 no.1 s.8
• /
• pp.100-110
• /
• 2001

In this paper, we investigated several buffer management schemes for the design of shared-memory type ATM switches, which can enhance the utilization of switch resources and can support quality-of-service (QoS) functionalities. Our results show that dynamic threshold (DT) scheme demonstrate a moderate degree of robustness close to pushout(PO) scheme, which is known to be impractical in the perspective of hardware implementation, under various traffic conditions such as traffic loads, burstyness of incoming traffic, and load non-uniformity across output ports. Next, we considered buffer management strategies to support QoS functions, which utilize parameter values obtained via connection admission control (CAC) procedures to set tile threshold values. Through simulations, we showed that the buffer management schemes adopted behave well in the sense that they can protect regulated traffic from unregulated cell traffic in allocating buffer space. In particular, it was observed that dynamic partitioning is superior in terms of QoS support than virtual partitioning.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.35 no.6B
• /
• pp.954-961
• /
• 2010

Stream cipher was worse than block cipher in terms of security, but faster in execution speed as an advantage. However, since so far there have been many algorithm researches about the execution speed of block cipher, these days, there is almost no difference between them in the execution speed of AES. Therefore an secure and fast stream cipher development is urgently needed. In this paper, we propose a 32bit output fast stream cipher, AA32, which is composed of ASR(Arithmetic Shifter Register) and simple logical operation. Proposed algorithm is a cipher algorithm which has been designed to be implemented by software easily. AA32 supports 128bit key and executes operations by word and byte unit. As Linear Feedback Sequencer, ASR 151bit is applied to AA32 and the reduction function is a very simple structure stream cipher, which consists of two major parts, using simple logical operations, instead of S-Box for a non-linear operation. The proposed stream cipher AA32 shows the result that it is faster than SSC2 and Salsa20 and satisfied with the security required for these days. Proposed cipher algorithm is a fast stream cipher algorithm which can be used in the field which requires wireless internet environment such as mobile phone system and real-time processing such as DRM(Digital Right Management) and limited computational environments such as WSN(Wireless Sensor Network).

• Spatial Information Research
• /
• v.1 no.1
• /
• pp.73-87
• /
• 1993

This paper reviews the topic of GIS, the academic setting of GIS, GIS model curricula and the possibility GIS education in Korea. The topics which might be included in a science of geographic information consist of data collection and measurement, data capture, spatial statistics, data modeling and theories of spatial data, data structures, algorithms and processes, display, analytical tools, institutional, managerial and ethical issues. The problems in teaching a course on GIS in higher education are reviewed. Because of their technological, integrative, and rapidly changing nature, GIS pose major challenges to their education system which it is ill equipped to meet. In higher education a number of initiatives have been taken to provide education about and training with, GIS. The possible GIS curricula are suggested. These curricula are divided into 3 major sections, relating GIS context, technical issues and application issues. The prospects of GIS appears lo depend largely upon the future cooperation of academia, government, and industry

• Progress in Medical Physics
• /
• v.15 no.4
• /
• pp.186-191
• /
• 2004

The periodic Quality Assurance (QA) of each radiation treatment related equipments is important one, but quality assurance of the radiation treatment planning system (RTPS) is still not sufficient rather than other related equipments in clinics. Therefore, this study will present and test the periodic QA program to compare, evaluation the efficiency of the treatment planning systems. This QA program is divided to terms for the input, output devices and dosimetric data and categorized to the weekly, monthly, yearly and non-periodically with respect to the job time, frequency of error, priority of importance. CT images of the water equivalent solid phantom with a heterogeneity condition are input into the RTPS to proceed the test. The actual measurement data are obtained by using the ion chamber for the 6 MV, 10 MV photon beam, then compared a calculation data with a measurement data to evaluate the accuracy of the RTPS. Most of results for the accuracy of geometry and beam data are agreed within the error criteria which is recommended from the various advanced country and related societies. This result can be applied to the periodic QA program to improve the treatment outcome as a proper model in Korea and used to evaluate the accuracy of the RTPS.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.19 no.2
• /
• pp.65-72
• /
• 2015

Performance tests of a turbopump for the developing 7-tonf liquid rocket engine were conducted. The performance of turbopump components and their power matching were measured and examined firstly under the LN2 and water environment. In the real propellant(LOX and kerosene) environment tests, design and off-design performances of turbopump were fully verified. During the off-design tests, turbopump running time was set the same as engine operating time and pump inlet pressure were set lower than nominal operating value in order to investigate pump suction capability. It have been verified that subject turbopump satisfies required performance - flow rate, head, suction performance and operational time - in the operating regime of developing liquid rocket engine.