• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.7
• /
• pp.1296-1306
• /
• 2015

Nowadays the research of energy saving on the IP networks have been studied the various methods in many research institutes. This paper suggests the energy saving method in IP networks which have the various energy profiles, and analyzes its energy saving characteristics in detail. Especially this paper proposes the energy profile based OSPF routing method which have the selectable weighted value in OSPF metric and energy consumption in IP network. This paper analyzes the energy saving effects of the various situations to minimize the energy consumption using the various weighted value on the proposed scheme. The results show that the energy saving efficiency can get about 67% at in ingress input load ${\rho}=0.5$ by using random energy profiles in IP networks. Although the number of hops is a slight increased due to routing the paths for the minimum energy consumption in the algorithm of this method, the increment hop number is limited the mean 1.4 hops. This paper confirms that the energy profile of core router has the large effects of energy saving than the energy profile of edge router, and the proposed method has the excellent energy saving characteristics in IP networks.

• Journal of KIISE:Software and Applications
• /
• v.32 no.3
• /
• pp.227-235
• /
• 2005

In the embedded system domain, both memory requirement and energy consumption are great concerns. To save memory and energy, the 32 bit ARM processor supports the 16 bit Thumb instruction set. For a given program, the Thumb code is typically smaller than the ARM code. However, the limitations of the Thumb instruction set can often lead to generation of poorer quality code. To generate codes with smaller size but a little slower execution speed, Krishnaswarmy suggests a profiling guided selection algorithm at module level for generating mixed ARM and Thumb codes for application programs. The resulting codes of the algorithm give significant code size reductions with a little loss in performance. When the instruction set is selected at module level, some functions, which should be compiled in Thumb mode to reduce code size, are compiled to ARM code. It means we have additional code size reduction chance. In this paper, we propose a profile guided selection algorithm at function level for generating mixed ARM and Thumb codes for application programs so that the resulting codes give additional code size reductions without loss in performance compared to the module level algorithm. We can reduce 2.7％ code size additionally with no performance penalty

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.6 no.2
• /
• pp.9-14
• /
• 2010

The ground source heat pump system is increasingly being considered as an alternative to traditional heating and cooling systems to reduce the emission of ground house gases. In this paper, A series of numerical analysis for energy piles has been performed focusing on heat transfer efficiency, performance and thermal stress. Results of numerical analyses for the W-shape type shows more efficient heat exchange transfer than the coil type. From results of the thermo-mechanical analysis, it is shown that the concentration of thermal stress occurs around the circulating pipe and the interfaces between different materials. The largest deformation caused by thermal stress is observed in the energy pile.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.8 no.4
• /
• pp.8-16
• /
• 2012

The use of energy pile foundation has been increased for economic utilization of geothermal energy. This paper describes an experimental and numerical study on thermal response tests (TRTs) using W and 3U-shaped ground heat exchangers (GHEs) in precast-high strength concrete (PHC) energy piles. Ground thermal conductivity and borehole thermal resistance were measured and compared with those numerical analysis. W-shpaed GHE showed higher heat transfer behavior than 3U-shaped one because of different conditions such as pile size and volume of grout. That is, ground thermal conductivity using W-shaped GHE was higher than that of 3U shaped GHE, and borehole thermal resistance vice versa. The relative error of borehole resistance values between numerical and analytical solution was less than 5%.

• Journal of the Korea Society of Computer and Information
• /
• v.14 no.4
• /
• pp.9-17
• /
• 2009

In this paper, we propose a dynamic load distribution technique at the operating system level in mobile storage systems with a heterogeneous storage pair of a small form-factor and disk and a flash memory, which aims at saving energy consumption as well as enhancing I/O performance. Our proposed technique takes a combinatory approach of file placement and buffer cache management techniques to find how the load can be distributed in an energy and performance-aware way for a heterogeneous mobile storage air of a hard disk and a flash memory. We demonstrate that the proposed technique provides better experimental results with heterogeneous mobile storage devices compared with the existing techniques through extensive simulations.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.86.1-86.1
• /
• 2010

예비개질기(Pre-reformer)는 중대형 내부개질형 용융탄산염 연료전지(MCFC) 시스템에서 다양한 연료를 사용하기 위한 필수적인 화학반응기이다. 예비개질기는 스택 전단에 설치함으로서 스택 내부의 열균형을 유지하고, 다양한 원료를 연료로 이용할 수 있도록 하며, 황화물로부터 후단의 개질촉매 및 전극촉매를 보호하여 주개질 반응의 부담을 감소시켜 MCFC 시스템의 내구성 향상의 중요한 역할을 한다. 본 연구는 예비개질 반응기 설계에 CFD 모델링을 적용하기에 앞서 파일롯 반응기 내 농도/ 온도 구배를 측정하고자 하는 목적으로 수행되었다. 반응가스로는 천연가스 내 고차탄화수소(C2 이상) 중 상대적으로 높은 농도를 가진 에탄을 이용하였고, MCFC용 예비개질기의 운전특성을 고려하여 비교적 낮은 온도와 높은 수증기/탄소 비에서 단열반응기로 실험을 진행하였다. 향후 본 실험결과를 이용하여 CFD 모델링에 대한 검증을 수행할 예정이며, 하수처리장부생가스(ADG)/ 매립지 가스(LFG)용 MCFC 시스템을 위한 예비개질기 설계에도 적용을 하고자 한다.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.9
• /
• pp.54-61
• /
• 1998

A new Triple well structure is proposed for improved latch-up immunity at deep submicron CMOS device. Optimum latch-up immunity process condition is established and analyzed with varying ion implantation energy and amount of dose and also compared conventional twin well structure. Doping profile and structure are investigated using ATHENA which is process simulator, and then latch-up current is calculated using ATLAS which is device simulator. Two types of different process are affected by latch-up characteristics and shape of doping profiles. Finally, we obtained the best latch-up immunity with 2.5[mA/${\mu}{m}$] trigger current using 2.5 MeV implantation energy and 1$\times$10$^{14}$ [cm$^{-2}$ ] dose at p-well

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.1 no.1
• /
• pp.102-111
• /
• 1998

Ocean monitoring facilities are divided into two types, fixed type and floating type. This paper deals with wane load calculation and mooring system for a floating monitoring facility. Wave load and drift forces are calculated for an example case of floating monitoring buoy To enlarge holding power of anchor, circular pile model test was performed. A program for horizontal force of circular pile in sand was made and the calculated result showed fairy good agreement with the result of model test. It is expected that this method will provide good estimation for the holding power of the prototype of circular pile anchor which is relied upon SCUBA activity for installation.

• Proceedings of the IEEK Conference
• /
• 1998.06a
• /
• pp.331-334
• /
• 1998

p형 실리콘 기판위에 100.angs.의 초기 산화막을 성장시킨 후 붕소(B)와 인(P)을 1MeV 이온주입 에너지로 4.dec. tilting하여 붕소의 도즈량은 1*10/녀ㅔ 13/[cm/sup -2/]까지, 인은 1*10/sup 13/[cm/sup -2]로부터 1*10/sup 14/[cm/sup -2/] 까지 변화시키며 이온 주입하였다. 이온주입 후 RTA 로서 열처리 하였으며, 열처리 시간은 10초에서 40초까지,열처리 온도를 1000.deg.C에서 1100.deg.C까지 변화하였다. 이후 기파낸의 불순물의 프로파일 및 미세 결함의 분포를 분석하기 위하여, SIMS, SRP, XTEM 분석을 실시하였고, 이를 monte-carlo 모ㅓ델로서 시뮬레이션하여 비교하였다. SIMS 분석 결과 열처리 온도와 시간이 증가할수록 접합깊이가 증가하였고, 프로파일이 넓어짐을 볼수 있다. SRP 측정에서 붕소는 주해거리 (Rp)값은 1.8.mu.m~1.9.mu.m, 인의 경우는 1.1.mu.m~1.2.mu.m의 주행거리 (Rp) 값이 나타났다. XTEM 분석결과 붕소의 경우 열처리에 전후에도 결함을 볼수 없었고, 인의 경우 열처리 이후에 실리콘 결정내부에 있던 산소(O)와 인(P)우너자의 pinning효과에 의해 전위다이폴을 형성하여 표면근처로 성장함을 볼수 있었다.

• Journal of the Korean Geotechnical Society
• /
• v.30 no.4
• /
• pp.93-99
• /
• 2014

Use of geothermal energy has been increased for its economical application and environmentally friendly utilization. Particularly, for energy piles, a spiral coil type ground heat exchanger (GHE) is more preferred than line type GHEs such as U and W shaped GHEs. A PHC energy pile with spiral coil type GHE was installed in an area of partially saturated dredged soil deposit, and a thermal response test (TRT) was conducted for 240 hours under a continuous operation condition. Besides, remolded soil samples from different layers were collected in the field, and soil specimens were reconstructed according to the field ground condition. Non-steady state probe methods were conducted in the lab, and ground thermal conductivity and thermal diffusivity were measured for the different soil layers. An equivalent ground thermal conductivity was calculated from the lab test results and it was compared with the field TRT result. The difference was less than 5%, which advocates the use of an equivalent ground thermal conductivity for the multi-layered ground. Furthermore, this paper also represents an equivalent ground thermal diffusivity evaluation method which is another very important design parameter.