• Journal of IKEEE
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• v.18 no.2
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• pp.198-205
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• 2014

As the development of information technology, the interests in tiny applications such as wearable devices, portable devices and RFID are increased and the importance of low-area encryption circuit is emphasized. This paper proposes a compact architecture of AES-based encryption circuit suitable for tiny applications. The circuit area is reduced by minimizing storage space and sharing computation resources. The synthesized gate-level circuit using 65nm standard cell library consists of 2,241 gates and two $8{\times}16$-bit SRAMs. It can process data at a rate of 50.57Mbits per second. Therefore, the proposed encryption circuit is suitable for various applications requiring very small encryption circuit.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.192-194
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• 2007

본 논문에서는 금속체에 RFID 태그 안테나를 부착 시 태그 인식이 가능하도록 태그 안테나를 설계 및 제작하였다. 기존 도체 태그용 RFID 안테나는 크기가 큰 단점이 있으나, 본 논문에서는 미앤더 구조를 제안하여 안테나 크기의 소형화에 중점을 두었다. 2 개의 유전체를 결합하여 도체에서의 특성 감소를 최소화 하였고 급전부와 단락부의 간격조절로 사용된 칩 저항인 77-j100옴과의 conjugate 매칭을 유도 하였다. 태그의 크기는 30 ${\times}$ 40 mm로 기존의 태그안테나에 비해 소형임에도 임피던스 특성을 얻을 수 있음을 확인하였다. 대역폭은 UHF대역을 만족하는 $900MHz{\sim}921MHz$를 얻었고, 도체에 태그를 부착 후 인식거리 측정에 있어서도 기존 제품과 유사한 특성을 얻었다.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.3
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• pp.231-242
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• 2004

Remote control and monitoring of information appliances require RTOS and TCP/IP network module to communicate each other. Traditional TCP/IP protocol stacks, however, require relatively large resources to be useful in small 8 or 16-bit systems both in terms of code size and memory usage. It motivates design and implementation of micro TCP/IP that is lightweight for embedded systems. Micro embedded web server is also required to control and monitor information appliances through the Web. In this paper, we design and implement micro TCP/IP and Web server for information appliances. For this goal, we investigate requirements for the interoperability of embedded systems with the Internet and the Web-based control of embedded systems. Next, we compare our micro TCP/IP protocol stack with that of RTIP and QPlus in terms of object code size and performance. The size of micro TCP/IP protocol stack can be reduced by 3/2 and 1/4, respectively, comparing with that of RTIP and QPlus. We also show that the performance of our micro TCP/IP is similar to that of RTIP and QPlus since it handles 2.9Mbps when delayed ACK is not adapted.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.454-465
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• 2020

Fire simulations were performed using the Fire Dynamics Simulator (FDS) software to examine the vent flow and temperature in the engine room of a small ship. A diesel fire with a heat release rate of 10 kW was targeted, and the effects of the ceiling duct location, side vent existence and nonexistence, and side vent size were investigated. The existence or nonexistence of the side vent and its size considerably affected the smoke behavior, mass flow rate through the vent, and temperature. When the side vent was not installed or was small, the smoke layer reached the floor in the engine room. In addition, as the side vent size increased, the mass flow rate through the vent increased with decreasing temperature value. However, the effects of the ceiling duct location on the smoke behavior, mass flow rate through the vent, and temperature seemed to be relatively minor compared to those of the side vent size. Therefore, to improve the fire safety of the engine room in a small ship, the side vent size is considered to be a more important design factor than the ceiling duct location.

• Korean Journal of Environmental Biology
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• v.24 no.1 s.61
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• pp.7-18
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• 2006

Samples were collected from five stations monthly from October 2003 to September 2004 to investigate seasonal variation of size structure of phytoplankton and relationship between size-fractionated phytoplankton and environmental factors in the Asan Bay. The contribution of large cells (microphytoplankton, $>20\;{\mu}m$) to total concentrations of chlorophyll $\alpha$ was higher than small cells (nanophytoplankton, $3\sim20\;{\mu}m$; picophytoplankton, $<3\;{\mu}m$) during the sampling period. Especially, large cells contributed 80% to the total chlorophyll a from February, 2004 to April 2004 when chlorophyll $\alpha$ concentrations were high. The size structure of phytoplankton shifted from micro-size class to nano-size class and picophytoplankton rapidly increased when phytoplankton biomass decreased in May 2004. Microphytoplankton exhibited a high biomass in the upper region during winter-spring season whereas nano- and picophytoplankton showed two peaks in the middle-lower regions (Station 3,5) during spring and summer. Microphytoplankton are most likely controlled by water temperature and nutrient supply during the cold season whereas nano- and picophytoplankton may be affected by stratification, light exposure during the warm season.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2359-2368
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• 2013

Cone penetration tests (CPTs) have been increasingly used for site characterizations. However, the site investigations using CPTs are often limited due to soil conditions depending on the cone size and capacity of the CPT system. The small sectional area of a miniature cone improves the applicability of the CPT system due to the increased capacity of the CPT system. A continuous intrusion system using a coiled rod allows fast and cost effective site investigation. In this study, the performance of the continuous intrusion miniature cone penetration test (CIMCPT) system has been evaluated by comparison tests with the standard CPT system at several construction sites in Korea. The results show that the CIMCPT system has a same performance with the CPT system and has advantages on the mobility and applicability. According to field verification tests for scale effect evaluation, the cone tip resistance evaluated by CIMCPT overestimates by 10% comparing to standard CPTs. A crawler mounted with the CIMCPT system has been implemented to improve accessibility to soft ground, and has shown improvement over the truck type CIMCPT system. Therefore, the improved CIMCPT system can be utilized as a cost effective and highly reliable soil investigation methodology to detect the depth of soft ground and to evaluate soil classification.

• Electrical & Electronic Materials
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• v.17 no.4
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• pp.16-22
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• 2004

최근 나노기술의 발달로 다양한 나노구조체가 제작되었으며, 이러한 나노구조체를 바이오센서에 응용하고자하는 연구가 매우 활발하게 진행되고 있다. 나노구조체가 바이오센서 물질로 관심을 끄는 이유는 검출하고자하는 표적물질의 크기가 일반적으로 나노구조체의 크기와 비슷하므로 감도가 매우 좋은 센서의 제작이 가능할 뿐 아니라 센서의 소형화 및 집적화가 가능하기 때문이다.(중략)

• Journal of the KSME
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• v.56 no.9
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• pp.44-48
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• 2016

실제 크기의 로켓엔진은 수많은 예산이 소요되기 때문에 새롭게 설계된 엔진에 대하여 비행모델의 제작 및 실험연구는 예산과 위험성 때문에 매우 제한적으로 시행된다. 따라서 비행모델의 설계를 확정하기 위한 개발단계에서는 실제 크기의 로켓엔진의 특성을 나타낼 수 있는 소형 액체로켓을 제작하여 시험평가를 수행하게 된다. 이 글에서는 이러한 축소형 연소기 관련 연구동향을 알아보고자 한다.

• The Optical Journal
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• v.7 no.4 s.38
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• pp.31-34
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• 1995

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.602-612
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• 2013

In this paper, a design and fabrication of miniaturized 5.3 GHz reflection type $360^{\circ}$ analog phase shifter with branch line coupler and $360^{\circ}$ variable reactance load. In order to miniaturize phase shifter, novel branch line coupler is proposed. The novel branch line coupler is miniaturized using transformation of transmission line to T and ${\pi}$ type equivalent circuit. The miniaturized branch line coupler has small size of above 50 % compared with conventional branch line coupler. For wide phase shift range, $360^{\circ}$ variable reactance load structure is adopted. Especially, the structure was improved for linear phase shift by adding transmission line which acts as an impedance transformer. The improved structure was miniaturized using the equivalent lumped-element of transmission line. The fabricated phase shifter with $15{\times}15mm^2$ shows wide phase shift of above $480^{\circ}$, the insertion loss of -4~-6 dB and the reflection loss of below -20 dB at 5.3 GHz under 0~10 V control voltage range.