Comparison of Different Deep Learning Optimizers for Modeling Photovoltaic Power

Poudel, Prasis,Bae, Sang Hyun,Jang, Bongseog The Basic Science Institute Chosun University 2018 조선자연과학논문집 Vol.11 No.4

Comparison of different optimizer performance in photovoltaic power modeling using artificial neural deep learning techniques is described in this paper. Six different deep learning optimizers are tested for Long-Short-Term Memory networks in this study. The optimizers are namely Adam, Stochastic Gradient Descent, Root Mean Square Propagation, Adaptive Gradient, and some variants such as Adamax and Nadam. For comparing the optimization techniques, high and low fluctuated photovoltaic power output are examined and the power output is real data obtained from the site at Mokpo university. Using Python Keras version, we have developed the prediction program for the performance evaluation of the optimizations. The prediction error results of each optimizer in both high and low power cases shows that the Adam has better performance compared to the other optimizers.

Mathematical Approach on Composition of Nomination Committee for University President Election

Yi, Sucheol,Heo, Sunyeong The Basic Science Institute Chosun University 2016 조선자연과학논문집 Vol.9 No.1

The university president direct election system in Korea had begun in 1987 as a movement of college democratization in the 1980s after 6.29 Declaration. Since then, many national/private universities had adopted the election system. However, it has posed many problems and it caused a sharp division of opinions between those who approve and disapprove the direct election system. Since 2005, the government has made official of the reformation and/or abolition of the university president direct election system, and has kept pushing for universities to give up the direct election system. Now, only 3 or 4 universities hold on to the system, and many universities have changed into the indirect election system. In the indirect election, a key is the composition of president nomination committee, which confirms the university members's variety. Many universities adopting the indirect election system have used simple random sampling, like drawing lots, to compose the president nomination committee. However, drawing lots has a problem that it has large possibility of composing a biased committee. This research suggests systematic sampling as an alternative to drawing lots. A numerical analysis was conducted using a data of a university in which the indirect election was implemented recently. The drawing lots gave the biased nomination committee. On the other hand, the systematic sample improves the problem and confirms more the variety of all members.

The Universe and Particle Physics

Kim, Chung Wook CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

A pedagogical review of modern cosmology which attempts to describe the birth of the Universe and its evolution, and particle physics that is supposed to explain the microscopic particle world is presented with emphasis on their inter-relationship. I first describe the present Universe that we live in and point out many successes of the modern cosmology and its unsolved problems. After a short summary of recent developments in particle physics, I discuss how the knowledge of particle physics has made spectacular advances possible in modern cosmology. I argue that the ultimate understanding of particle physics may solve the mystery of the creation of the Universe and its evolution.

A Study on the Use-Actual Conditions of Reading-Room In the University Library : Focused on the University Libraries in Chunnam Area

Lee, Cheongwoong,Choi, Sukchang,Kim, yangsuk CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

Although reading room in library is the important space to be corresponded flexibly to the change of educational methods and systems, most of the library users have a negative recognition of the environment of reading room and then the improvement and consideration of the facilities are urgently needed. This study is to investigate use-actual condition, facility condition and plane composition of the reading room which is the core space of library for collecting, arranging, analyzing and keeping data for research and educational activity of users. The national universities use the closed reading room type as the operating method of library, but it should be converted into open typed reading room which connects the users with books and the reading system by themes which can seek the division of function and efficiency is accepted.

The Partial Differential Equations on Some Manifolds

Jung, Yoon-Tae,Shin, Cheol-Guen CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

In this paper, we consider the problem of achieving constant scalar curvature when (B,gB) is a compact Riemannian manifold and (F,gF) is a pseudo-Riemannian manifold. In our study of this case, we apply the method of upper and lower solutions and also variational considerations.

On the Operating Regimes of Count-Current Flow Limit in a Vertical Two Phase Flow

Oh, Yoolkwon,Park, Keunuk CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

A set of experiments of Counter-Current Flow Limit(CCFL or Flooding) was performed to improve the drawbacks of Wallis' correlation which neglects the effects of channel size, channel length, injection method and the boundary conditions at the inlet of liquid and gas phase. In these experiments using water and air, the followings were found; i)The effects of channel size and length were quite significant. In large tubes(D>20mm), the flooding front occurred at the bottom of the channel and when the gas flow increased the front moved upward; however, in small tubes(D<20mm), there were no upward movement of flooding front and the flooding just occurred at the liquid inlet. ii) The effect of water inlet device was not as significant as that of channel length though the inlet boundary conditions front reached the inlet of water injection device, a newly reduced flow condition was set up and resulted in another flooding corresponding to the new condition.

A Practical Approach to the Quantitative Flaw Characterization in Weldments-The Intelligent Ultrasonic Evaluation System

Ko, Sun-Pil,Kim, Hak-Joon,Lee, Hyun,Song, Sung-Jin CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

Quantitative flaw characterization in weldments in one of the key issues in the nondestructive evaluation of various structers and machine parts. For the convenience of performing this task in the real practical field application, an intelligent ultrasonic evaluation system is currently being developed. This system is composed of two parts; 1) a multi-axis portable scanner system that can do consistent and efficient acquisition of ultrasonic signals from flaws in weldments at various interrogating points and angels, and 2) an intelligent ultrasonic flaw analysis software which can perform the flaw classification and sizing based on these ultrasonivc flaw signals. Here, we present recent progress in the development of this intellingent system including the design of the portable scanner body, the intelligent flaw classification software, and initial works to the intelligent equivalent flaw sizing.

Value for Money in Building Design : Benchmarking Alternative Early Design Solutions

Kim, Han Soo CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

Value for money for the clients is a theme that recently draws much attention of academics and practitioners. In essence, value is quality in relation to cost. In UK practice, traditional cost models are generally used by cost consultants as a means for comparatively evaluating or benchmarking alternative design solutions. These models have played a significant role in providing cost advice during the design process. However, the practice of early cost advice, which is based on traditional cost models, has been criticised by many authors. these criticisms focus around their inadequacy of representing and evaluating the quality dimension of design options and thus to enable its relationship with the cost-dimension to be explored during early design. This paper investigates characteristics upon which a cost-quality modelling technique for early design evaluation could be based. The significance of the development of such a model lies in providing a basis of defining value for money for the clients during early design.

The Derivation of Rating-Curve of the Tamjin River

Kim,Woon Joong,Jung, Nam Sun CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

The Korea Water Resource Corporation is planning to perfrm the water supply to Mokpo, Jangheung, and Youngam by constructing a dam in the Tamjin river, which is located at the southwestern coast. However, due to the lack of the basic data of stage and discharge and thd move of the watermark, some problems are issued in establishing the plans for the water resource. Thus, in this study, using the current-meter and the bar-buoys, the discharge was directly measured, and the rating-curve was derived being merging with the previous data. As there exists only the stage data as the previous water supply data, and the watermark was moved recently, the relative figure between the new watermark and the old watermark was drawn out to make use of the previous stage data. This study will make a great contribution to the establishment ofthe water resource plan for the Tamjin dam, which is tobe constructed soon.

Nuclear Facilities and Public Acceptance

Kim, Soong Pyung CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.2

The anti-nuclear movement related with nuclear power plant and radwaste disposal facility has been spread out widely in nuclear facility near area since the second half of 1980's. The direction of nuclear P.A. should be toward socio-cultural view for local resident's safety recognition and financial aids. Nuclear publicity may be a s preading work to transfer the public's common sence for the nuclear sagery from technological view to socio-cultural view. WHen financial is paid to local residents for accepting the nuclear related facility, the support must be decided according to reasonable criterion.