• Title/Summary/Keyword: Programming characteristics

Search Result 545, Processing Time 0.028 seconds

A Study on Optimal Operation of Microgrid Considering the Probabilistic Characteristics of Renewable Energy Generation and Emissions Trading Scheme (신재생에너지발전의 확률적인 특성과 탄소배출권을 고려한 마이크로그리드 최적 운용)

  • Kim, Ji-Hoon;Lee, Byung Ha
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.63 no.1
    • /
    • pp.18-26
    • /
    • 2014
  • A microgrid can play a significant role for enlargement of renewable energy sources and emission reduction because it is a network of small, distributed electrical power generators operated as a collective unit. In this paper, an application of optimization method to economical operation of a microgrid is studied. The microgrid to be studied here is composed of distributed generation system(DGS), battery systems and loads. The distributed generation systems include combined heat and power(CHP) and small generators such as diesel generators and the renewable energy generators such as photovoltaic(PV) systems, wind power systems. Both of thermal loads and electrical loads are included here as loads. Also the emissions trading scheme to be applied in near future, the cost of unit start-up and the operational characteristics of battery systems are considered as well as the probabilistic characteristics of the renewable energy generation and load. A mathematical equation for optimal operation of this system is modeled based on the mixed integer programming. It is shown that this optimization methodology can be effectively used for economical operation of a microgrid by the case studies.

An Reliable Non-Volatile Memory using Alloy Nano-Dots Layer with Extremely High Density

  • Lee, Gae-Hun;Kil, Gyu-Hyun;An, Ho-Joong;Song, Yun-Heup
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2010.02a
    • /
    • pp.241-241
    • /
    • 2010
  • New non-volatile memory with high density and high work-function metal nano-dots, MND (Metal Nano-Dot) memory, was proposed and fundamental characteristics of MND capacitor were evaluated. In this work, nano-dot layer of FePt with high density and high work-function (~5.2eV) was fabricated as a charge storage site in non-volatile memory, and its electrical characteristics were evaluated for the possibility of non-volatile memory in view of cell operation by Fowler-Nordheim (FN)-tunneling. Here, nano-dot FePt layer was controlled as a uniform single layer with dot size of under ~ 2nm and dot density of ${\sim}\;1.2{\times}10^{13}/cm^2$. Electrical measurements of MOS structure with FePt nano-dot layer shows threshold voltage window of ~ 6V using FN programming and erasing, which is satisfied with operation of the non-volatile memory. Furthermore, this structure provides better data retention characteristics compared to other metal dot materials with the similar dot density in our experiments. From these results, it is expected that this non-volatile memory using FePt nano-dot layer with high dot density and high work-function can be one of candidate structures for the future non-volatile memory.

  • PDF

Study on the Fabrication of Tunnel Type $E^2PROM$ and Its Characteristics (터널링형 $E^2PROM$ 제작 및 그 특성에 관한 연구)

  • Kim, Jong Dae;Kim, Sung Ihl;Kim, Bo Woo;Lee, Jin Hyo
    • Journal of the Korean Institute of Telematics and Electronics
    • /
    • v.23 no.1
    • /
    • pp.65-73
    • /
    • 1986
  • Experiment have been conducted about thin oxide characteristics according to O2/N2 ratio needed for EEPROM cell fabrication. As a result, we think that there is no problem even if we grow oxide layer with large O2/N2 ratio and short exidation time and when the water is implated by As before oxidation, the oxide breakdown field is about IMV/cm lower than that is not implanted. Especially, the thin oxide characteristic seems to be affected largely by wafer cleaning and oxidation in air. On the basis of these, tunnel type EEPROM cell is fabricated by 3um CMOS process and its characteristic is studied. Tunnel oxide thickness(100\ulcorner is chosen to allow Fowler-Nordheim tunneling to charge the floating gate at the desired programming voltage and tunnel area(2x2um\ulcorneris chosen to increase capacitive coupling ratio. For program operation, high voltage (20-22V) is applied to the control gate, while both drain and source are gdrounded. The drain voltage for erase is 16V. It is shown that charge retention characteristics is not limited by leakage in the oxide and program/erase endurance is over 10E4 cycles of program erase operation.

  • PDF

A Study on Threshold Voltage Degradation by Loss Effect of Trapped Charge in IPD Layer for Program Saturation in a MLC NAND Flash Memory (멀티레벨 낸드 플래쉬 메모리 프로그램 포화 영역에서의 IPD 층에 트랩된 전하의 손실 효과에 의한 문턱 전압 저하 특성에 대한 연구)

  • Choi, Chae-Hyoung;Choi, Deuk-Sung;Jeong, Seung-Hyun
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.24 no.3
    • /
    • pp.47-52
    • /
    • 2017
  • This research scrutinizes the data retention characteristics of the MLC NAND Flash Memory instigated by the loss effect of trapped charge when the memory is in the state of program saturation. It is attributed to the threshold voltage saturation phenomenon which engenders an interruption to the linear increase of the voltage in the memory cell. This phenomenon is occasioned by the outflow of the trapped charge from the floating gate to the control gate, which has been programmed by the ISPP (Incremental Step Pulse Programming), via Inter-Poly Dielectric (IPD). This study stipulates the significant degradation of thermal retention characteristics of threshold voltage in the saturation region in contrast to the ones in the linear region. Thus the current study evaluates the data retention characteristics of voltage after the program with a repeated reading test in various measurement conditions. The loss effect of trapped charge is found in the IPD layer located between the floating gate and the control gate especially in the nitride layer of the IPD. After the thermal stress, the trapped charge is de-trapped and displays the impediment of the characteristic of reliability. To increase the threshold saturation voltage in the NAND Flash Memory, the storage ability of the charge in the floating gate must be enhanced with a well-thought-out designing of the module in the IPD layer.

On the Direction of the Computer Algorithm Education Based on Conceptual Algorithms (개념적 알고리즘에 기반 한 컴퓨터 알고리즘 교육의 방향)

  • Moon, Gyo-Sik
    • Journal of The Korean Association of Information Education
    • /
    • v.11 no.1
    • /
    • pp.29-38
    • /
    • 2007
  • Computer programming in computer education draws much attention recently. Encouraged by the increased tendency of acquiring logical ability and creativity through learning, various attempts have been made to develop them through learning computer programming in the area of computer education as well. The fact that a computer program is the representation of a computer algorithm expressed in a computer language makes us realize that the devise of a logical method for a solution - i.e., the design of an algorithm - is the key to the solution of a problem. Recognizing the importance of computer algorithm would lead us to such a point that systematic investigations for directional establishment for algorithm education are necessary. We observe that researches on teaching computer algorithm have concentrated mostly on specific problems such as sorting and searching, which can be characterized as problem-dependent and individual. In this paper, the idea of conceptual algorithm is stated from the standpoint of conceptual types of problem-solving methods which are considered as problem-independent and collective. A novice approach to algorithm education based on the characteristics of types of conceptual algorithms is proposed for the purpose of developing systematic, problem-independent, algorithmic problem-solving capabilities of learners, which is widely different from the current methods of individual and problem-dependent algorithm education.

  • PDF

Study for the Plant Layout Optimization for the Ethylene Oxide Process based on Mathematical and Explosion Modeling (수학적 모델과 폭발사고 모델링을 통한 산화에틸렌 공정의 설비 배치 최적화에 관한 연구)

  • Cha, Sanghoon;Lee, Chang Jun
    • Journal of the Korean Society of Safety
    • /
    • v.35 no.1
    • /
    • pp.25-33
    • /
    • 2020
  • In most plant layout optimization researches, MILP(Mixed Integer Linear Programming) problems, in which the objective function includes the costs of pipelines connecting process equipment and cost associated with safety issues, have been employed. Based on these MILP problems, various optimization solvers have been applied to investigate the optimal solutions. To consider safety issues on the objective function of MILP problems together, the accurate information about the impact and the frequency of potential accidents in a plant should be required to evaluate the safety issues. However, it is really impossible to obtain accurate information about potential accidents and this limitation may reduce the reliability of a plant layout problem. Moreover, in real industries such as plant engineering companies, the plant layout is previously fixed and the considerations of various safety instruments and systems have been performed to guarantee the plant safety. To reflect these situations, the two step optimization problems have been designed in this study. The first MILP model aims to minimize the costs of pipelines and the land size as complying sufficient spaces for the maintenance and safety. After the plant layout is determined by the first MILP model, the optimal locations of blast walls have been investigated to maximize the mitigation impacts of blast walls. The particle swarm optimization technique, which is one of the representative sampling approaches, is employed throughout the consideration of the characteristics of MILP models in this study. The ethylene oxide plant is tested to verify the efficacy of the proposed model.

Development of a Multiobjective Optimization Algorithm Using Data Distribution Characteristics (데이터 분포특성을 이용한 다목적함수 최적화 알고리즘 개발)

  • Hwang, In-Jin;Park, Gyung-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.34 no.12
    • /
    • pp.1793-1803
    • /
    • 2010
  • The weighting method and goal programming require weighting factors or target values to obtain a Pareto optimal solution. However, it is difficult to define these parameters, and a Pareto solution is not guaranteed when the choice of the parameters is incorrect. Recently, the Mahalanobis Taguchi System (MTS) has been introduced to minimize the Mahalanobis distance (MD). However, the MTS method cannot obtain a Pareto optimal solution. We propose a function called the skewed Mahalanobis distance (SMD) to obtain a Pareto optimal solution while retaining the advantages of the MD. The SMD is a new distance scale that multiplies the skewed value of a design point by the MD. The weighting factors are automatically reflected when the SMD is calculated. The SMD always gives a unique Pareto optimal solution. To verify the efficiency of the SMD, we present two numerical examples and show that the SMD can obtain a unique Pareto optimal solution without any additional information.

Evaluation of Fuel Economy and Performance for 2WD and 4WD Hybrid Electric Vehicle Based on Backward Simulation (2륜 및 4륜 구동 하이브리드 전기 자동차의 후방향 시뮬레이션 기반 연비 및 성능 평가)

  • Jeong, Jongryeol;Kim, Hyungkyoon;Kim, Kiyoung;Lim, Wonsik;Cha, Suk Won
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.22 no.1
    • /
    • pp.174-182
    • /
    • 2014
  • Recently, not only common types of hybrid electric vehicle (HEV) such as series or parallel but many other types of HEVs including 4WD hybrid electric vehicle have been developed and released. In this study, analysis of fuel economy and driving performance for 2WD and 4WD HEV are conducted using backward simulation based on dynamic programming. To analyze the characteristics of 4WD HEV, tire slip model based on vehicle dynamics was applied to the backward simulation program. As a result, 2WD HEV shows better fuel economy than 4WD HEV because of relatively simple configuration. However, in a severe road condition, 4WD HEV shows better driving performance that 2WD HEV had about 6% of impossible time to follow the driving cycle though the 4WD HEV had no impossible time.

Educational Framework for Interactive Product Prototyping

  • Nam Tek-Jin
    • Archives of design research
    • /
    • v.19 no.3 s.65
    • /
    • pp.93-104
    • /
    • 2006
  • When the design profession started, design targets were mainly static hardware centered products. Due to the development of network and digital technologies, new products with dynamic and software-hardware hybrid interactive characteristics have become one of the main design targets. To accomplish the new projects, designers are required to learn new methods, tools and theories in addition to the traditional design expertise of visual language. One of the most important tools for the change is effective and rapid prototyping. There have been few researches on educational framework for interactive product or system prototyping to date. This paper presents a new model of educational contents and methods for interactive digital product prototyping, and it's application in a design curricula. The new course contents, integrated with related topics such as physical computing and tangible user interface, include microprocessor programming, digital analogue input and output, multimedia authoring and programming language, sensors, communication with other external devices, computer vision, and movement control using motors. The final project of the course was accomplished by integrating all the exercises. Our educational experience showed that design students with little engineering background could learn various interactive digital technologies and its' implementation method in one semester course. At the end of the course, most of the students were able to construct prototypes that illustrate interactive digital product concepts. It was found that training for logical and analytical thinking is necessary in design education. The paper highlights the emerging contents in design education to cope with the new design paradigm. It also suggests an alterative to reflect the new requirements focused on interactive product or system design projects. The tools and methods suggested can also be beneficial to students, educators, and designers working in digital industries.

  • PDF

Development of STEAM Program using App Inventor -Focusing on the Concept of Speed in Elementary Science Education- (앱인벤터를 활용한 STEAM 프로그램 개발 -초등학교 과학의 '속력' 개념을 중심으로-)

  • Shin, Seungki;Choi, Ikseon;Bae, Youngkwon
    • The Journal of the Korea Contents Association
    • /
    • v.15 no.4
    • /
    • pp.530-544
    • /
    • 2015
  • We live in the modern society which is called as Knowledge-Information society. The national and social goal is to raise the creative person for preparing the rapidly changing society. Thus, the schools and families concentrate on and effort to enhance the creativity and problem solving ability. Specially, the school is pushing forward the STEAM education and Software education for raising the creativity person and enhancement of national competitiveness. In this study, we suggested for STEAM education the way how we utilize the App Inventor which was supported by MIT and came up as a computer programming language for Software education, and we verified and evaluated through professional group verification. We completed STEAM instructional design according to the results from the professional group verification, and we suggested the authentic instruction for STEAM education. In addition, we suggested the further prospects of Software education and instructions through going through the characteristics and application plan of App Inventer in terms of educational computer programming language.