• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.444-461
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• 2016

A power-saving mechanism for smartphone devices is developed by analyzing the features of data that are received from Internet of Things (IoT) sensors devices to optimize the data processing policies. In the proposed GreenIoT architecture for power-saving in IoT, the power saving and feedback mechanism are implemented in the IoT middleware. When the GreenIoT application in the power-saving IoT architecture is launched, IoT devices collect the sensor data and send them to the middleware. After the scanning module in the IoT middleware has received the data, the data are analyzed by a feature evaluation module and a threshold analysis module. Based on the analytical results, the policy decision module processes the data in the device or in the cloud computing environment. The feedback mechanism then records the power consumed and, based on the history of these records, dynamically adjusts the threshold value to increase accuracy. Two smart living applications, a biomedical application and a smart building application, are proposed. Comparisons of data processed in the cloud computing environment show that the power-saving mechanism with IoT architecture reduces the power consumed by these applications by 24% and 9.2%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.749-752
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• 2012

Recent social issues is energy issues, green computing has attracted attention. Active research on the power consumption of computer profiling is one of the various approaches for green computing. As a representative tool PowerAPI, PowerTop, JouleMeter, pTop, and EnergyChecker. These studies can be used to measure the power consumption of each computer device because it is based on a pure software. Based on this profiling process at the level of power consumption by performing the power consumption of each program can be analyzed. Therefore to identify the processes that consume a lot of power and control the total power consumption by reducing, also when designing the program, based on data profiling power enables the design of low-power programs, and ultimately can be oriented green computing. In this paper, by comparing and analyzing the associated representative studies, the ideal process level will draw on the characteristics of the power consumption profiler.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.491-494
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• 2011

We propose a green computing which similar to green chemistry; reduce the use of hazardous materials, maximize energy efficiency during the product' s lifetime, and promote the recyclability or biodegradability of defunct products and factory waste. Research continues into key areas such as making the use of computers as energy-efficient as possible, and designing algorithms and systems for efficiency-related computer technologies.

• Journal of Information Technology Services
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• v.7 no.4
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• pp.221-230
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• 2008

Green's relations are five equivalence relations that characterize the elements of a semigroup in terms of the principal ideals. The J relation is one of Green's relations. Although there are known algorithms that can compute Green relations, they are not useful for finding all J relations in the semigroup of all $n{\times}n$ Boolean matrices. Its computation requires multiplication of three Boolean matrices for each of all possible triples of $n{\times}n$ Boolean matrices. The size of the semigroup of all $n{\times}n$ Boolean matrices grows exponentially as n increases. It is easy to see that it involves exponential time complexity. The computation of J relations over the $5{\times}5$ Boolean matrix is left an unsolved problem. The paper shows theorems that can reduce the computation time, discusses an algorithm for efficient J relation computation whose design reflects those theorems and gives its execution results.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.3
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• pp.62-71
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• 1995

In the numerical analysis of incompressible unsteady Navier-stokes equation, large time is required for solving the pressure Poisson equation of the elliptic type at each time step. In this paper, a numerical analysis by the direct method is carried out to solve the pressure Poisson equation and the computing time is analyzed as mesh size increases. The pressure Poisson equation can be transformed to the boundary value problem by the Green theorem. The computing time for the convolution type of the domain integral can be reduced by using F.F.T. and the computing time in the direct method depends entirely on obtaining the solution of the boundary value problem. The numerical analysis on the known solutions is carried out and compared for the verification of the direct method. And the numerical analysis on the body boundary and domain decomposition problem are carried out with the computing time less than O($n^{3}$) in the (n.n) mesh.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.113-123
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• 2009

As environmental issues are emerging, many efforts are globally conducted to reduce waste of energies and resources for green growth, as well as low-carbon emitting and replacement of document papers with digital files and images. On the other hand, it may require much time and efforts for users to find the proper image files on the web, where enormous un-standardized digital files are flourishing. Therefore, power and resource consumption may also grow up again in searching and retrieving files. This paper suggests efficient system design and implementation for fast and precise massive image contents retrieval for saving the energies and resources. Eventually it will contribute to green growth in computing environment.

• Journal of Information Processing Systems
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• v.5 no.4
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• pp.175-186
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• 2009

Power consumed by modern computer systems, particularly servers in data centers has almost reached an unacceptable level. However, their energy consumption is often not justifiable when their utilization is considered; that is, they tend to consume more energy than needed for their computing related jobs. Task scheduling in distributed computing systems (DCSs) can play a crucial role in increasing utilization; this will lead to the reduction in energy consumption. In this paper, we address the problem of scheduling precedence-constrained parallel applications in DCSs, and present two energy- conscious scheduling algorithms. Our scheduling algorithms adopt dynamic voltage and frequency scaling (DVFS) to minimize energy consumption. DVFS, as an efficient power management technology, has been increasingly integrated into many recent commodity processors. DVFS enables these processors to operate with different voltage supply levels at the expense of sacrificing clock frequencies. In the context of scheduling, this multiple voltage facility implies that there is a trade-off between the quality of schedules and energy consumption. Our algorithms effectively balance these two performance goals using a novel objective function and its variant, which take into account both goals; this claim is verified by the results obtained from our extensive comparative evaluation study.

• Information Systems Review
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• v.11 no.2
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• pp.147-167
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• 2009

As global climate changes, the interest in environmental crisis is increasing and a number of international agreements and regulations against this crisis are being established. Global information technology(IT) corporations are building their own pro-environmental green IT strategies to cope with the regulatory measures. Green IT broadly refers to pro-environmental technologies designed to replace hazardous materials, maximize energy effectivity, and find alternative energies. In the current stage of the IT industry development, Green IT specifically refers to the technologies that deal with the server heat generation and the energy reduction in data center. This study defines the concept of Green IT and reviews its origin and necessity. Then, it examines the issues regarding Green IT industry in Korea as well as other countries and compares the Green IT strategies developed in each country. Reviewing the recent development of IT and data center market enables us to see that overall Green IT strategies focus on the establishment of Green Internet Data Centers. Therefore, this study analyzes the cases in which some domestic and foreign corporations introduced Green Data Centers in order to examine the protocol and legal requirements for building Green IT, the aspects of environmental evaluation and design, and specific strategies for launching Green IT strategies and its future assignments. The conclusions of this study are as follows. First, to introduce Green Data Center as a strategy to build Green IT, the government and corporations should cooperate with each other. Partial introduction at the initial stage is desirable because, through the process, mutual trust between the two parties can be built more smoothly. Second, CEO's determination to build Green IT and continue its operation is indispensable. CEO's are required to have clear understanding as to why Green IT needs to be built and how it should be constructed. Those who initiate the construction of Green Data Center for Green IT need to know the definition and necessity of Green IT while at the same time understanding the implicit meanings of Green IT. They also need to be aware of future-oriented values of Green Data Center and readjust their corporate business activities in the pro-environmental direction. Finally, not only the CEOs' pro-environmental activities but also the change of mind on the part of all corporate employees is required to realize Green IT. It should be remembered that pro-environmental Green IT starts with minor activities.

• Kyungpook Mathematical Journal
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• v.56 no.4
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• pp.1141-1160
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• 2016

In this paper, a symbolic algorithm for solving a regular initial value problem (IVP) for a system of linear differential-algebraic equations (DAEs) with constant coeffcients has been presented. Algebra of integro-differential operators is employed to express the given system of DAEs. We compute a canonical form of the given system which produces another simple equivalent system. Algorithm includes computing the matrix Green's operator and the vector Green's function of a given IVP. Implementation of the proposed algorithm in Maple is also presented with sample computations.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.10
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• pp.27-35
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• 2010

In wireless packet networks, energy and wireless resource efficiency is critical issue to addressed for wide deployment. To achieve the both goals of saving the mobile station's energy and increasing the wireless capacity, transmission power control is introduced to wireless packet networks. In the transmission power controled networks, it is not deeply studied on unfairness among transmissions with different power levels that reaches starvation. Through the performance analysis, this paper explains the throughput unfairness of high power transmission with the unfair media access probability owing to the contending node number difference and proposes a simple PHY-MAC cross layer approach.