• Korean Journal of Logic
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• v.16 no.3
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• pp.347-380
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• 2013

In this paper I will try to show how Wittgenstein criticized Frege's theory of meaning. Frege's theory of meaning can be compressed as sense-reference theory. Frege distinguishes between sense and reference on all the linguistic expressions. In particular, he regards that a sentence has sense and reference. This distinction was raised from, so to speak, the problem of identity sentences. Wittgenstein's "fundamental thought" of Tractatus Logico-Philosophicus is the key of his direct criticism of Frege's sense-reference theory. That is, it is an attack on Frege's thought that the reference of a sentence is a truth value and truth values are "objects themselves" (in Frege's meaning). According to Wittgenstein, such an object does not exist and according to his picture theory, the function of a name and that of a proposition are fundamentally different. By the way, Frege can reply justly to this criticism that it is insufficient. In short, Frege's 'sense' and 'reference' etc, are the technical terms. Hence Wittgenstein's decisive criticism of Frege's theory consists in accusing his theory of logical flaws. There is an another route to the sense and reference of a sentence which Frege introduces. In discourses of judgement stroke and content stroke in his Begriffsshrift and in those of horizontal stroke since his "Function and Concept", Frege deals with the sense and reference of a sentence. Wittgenstein criticize that the sense of a complex sentence such as ~p would by no means be determined by Frege's determination.

• Journal of Korea Port Economic Association
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• v.25 no.3
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• pp.251-268
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• 2009

This study analyzes price competition between two ports theoretically using a game model. We considered two cases: in Case I, consignors are located in a given position, and in Case II, consignors are distributed uniformally between two ports. The results are as follows. In Case I, the higher consignors' preferences for quality are, the more two ports' prices increase. As the locations of consignors are closer to Port H, the price of Port H increases and that of the low quality port(Port L) decreases. In addition, when transportation cost increases, the price of Port L decreases and the price of Port H tends to increase. If the quality of Port H improves, the price of the port H increases but the price of Port L is not clearly determined. In Case II, the higher consignors' preferences for quality are, the more two ports' prices increase. As transportation cost increases, the prices of both ports decrease but the price of Port L decreases twice as fast as that of Port H. In addition, if the quality of Port H improves, the price of Port H increases but the price of Port L decreases when transportation cost is high.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.81-90
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• 2021

There are various optimization problems in real world and research continues to solve them. An optimization problem is the problem of finding a combination of parameters that maximizes or minimizes the objective function. Harmony search is a population-based metaheuristic algorithm for solving optimization problems and it is designed to mimic the improvisation of jazz music. Harmony search has been actively applied to optimization problems in various fields such as civil engineering, computer science, energy, medical science, and water quality engineering. Harmony search has a simple working principle and it has the advantage of finding good solutions quickly in constrained optimization problems. Especially there are various application cases showing high accuracy with a low number of iterations by improving the solution through the empirical derivative. In this paper, we explain working principle of Harmony search and classify the leading research in recent 3 years, review them according to category, and suggest future research directions. The research is divided into review by field, algorithmic analysis and theory, and application to real world problems. Application to real world problems is classified according to the purpose of optimization and whether or not they are hybridized with other metaheuristic algorithms.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.39 no.1
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• pp.33-43
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• 2003

The midwater pair trawl which is being used at present in Korea have several problems. Firstly, it is difficult to control the net height on high towing speed. Secondly, net breaking often occurs owing to floats and thirdly, the volume of net on the net drum is so large. This study is aiming for examining the possibility of application for the Korean midwater pair trawl through the model experiment of non-float midwater pair trawl. The model of non-float midwater pair trawl was manufactured as 1/100 of the full scale net which is being used in bottom pair trawl for 850ps class considering the Tauti's Similarity law. The model experiment was carried out to analyze the opening efficiency according to the variation of lower warp length and the opening efficiency was investigated between th proto type and non-float type. The results obtained can be summarized as follows ; 1. The hydrodynamic resistance of non-float type was about 10~20% smaller than that of the proto type and it increased about 1ton according to the increase of dL at the condition of the same flow speed. The resistance acting on the lower warp decreased about 5% but that of the upper warp increased according to the increase of lower warp length (dL) at the condition of the same flow speed. 2. The net height of the non-float type decreased almost linearly according as the increased of flow speed and it increased in a logarithmic functional form with the increase of the lower warp length at the condition of the same flow speed. On the decreasing rate of the net height, the non-float type was lower than the proto type and the difference of the decreasing rate was about 12% at 3.0 knot, 25% at 4.0 knot, 25% at 4.0 knot respectively when dL was 30m. 3. The net width of non-float type was not varied so much as only 2m range and was larger than that of proto type. 4. The mouth area of non-float type decreased in a exponential functional form. On the decreasing rate of the mouth area, the non-float type was lower than the proto type. The filtering volume increased in a logarithmic functional form with increasing flow speed and the filtering volume of proto type decreased steeply over 3.0knot, but that of non-float type increased until 4.0knot. 5. The optimal length of lower warp was when the value of dL was about 30m and the optimal position of front weight was at the connection point of four net pendants.

• Journal of Korean Society of Transportation
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• v.23 no.4 s.82
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• pp.57-69
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• 2005

The goal of this paper is to develop freeway Origin-Destination (OD) demand estimation model using real-time traffic data collected from Freeway Traffic Management System (FTMS). In existing research, the micro-simulation models had been used to get a link distribution proportion by time process. Because of hi-level problem between the traffic flow model and the optimal OD solution algorithm, it is difficult for the existing models to be loaded at FTMS. The formulation of methodology proposed in this paper includes traffic flow technique to be able to remove the bi-level problem and optimal solution algorithm using a genetic algorithm. The proposed methodology is evaluated by using the real-time data of SOHAEAN freeway, South Korea.

• Journal of Educational Research in Mathematics
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• v.14 no.3
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• pp.305-325
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• 2004

This study is on the teaching-learning of parameter concept in secondary school mathematics. In our school mathematics curriculum, parameter concept is explicitly presented at high school mathematics textbook. But student have difficulty in understanding parameter concept because this concept is implicitly used in the textbook from 7-grade mathematics. Moreover, it is true that mathematics teacher give a little attention to student's understanding of parameter con- cept. In this study, we analyzed concept definition of parameter and the extension of parameter on the basis of preceding research, our mathematical curriculum, mathematical dictionaries. After that, we concluded that parameter is explicitly called in t where x= f(t), y= g(t) and parameter is implicitly treated in the learning of relation between quantities in our mathematical curriculum. We pointed to the importance of parameter concept in the successful learning of school algebra. Specially, when the level of algebra is in the learning of relation between quantities, parameter is the key concept for understanding and representing of families of equations or functions. In mathematics class, students have opportunity to reflect that what the role of each variable(parameter, dependent variable, independent variable etc.) is, and where the information which determines it comes from. It is for mathematical communications as well as learning school algebra. Therefore, mathematics teacher's didactical attention is more needed to student have a good concept image of parameter before they learn explicitly its concept definition.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.215-231
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• 2018

It is expected that the korean power retail market will be reorganized someday. Thus, this study analyzes the changes in consumers' utility level when new companies enter the retail market and offer various bundled services. For the analysis, the utility function of the consumers was estimated using the conjoint choice method. The results of the analysis can be summarized in two-folds. First, consumer will still prefer KEPCO in electricity sales. Therefore, difficulties can be expected when new companies enter the power retail market. Second, consumers do not favor bundled services in the electricity market also. Bundled services would not provide as much as utility each service provide separately.

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.242-249
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• 1997

Environmental control operations have been considerably contributed to the reduction of labor cost in both plastic film and glass greenhouses since government supported projects were begun. However, some problems are still remaining on the optimal environmental control and excessive operation due to an inflexible software regulating ventilation gear - reducers. The unadjustable software caused the damage of ventilation system, resulting in heat stresses of crops. This study was performed to develop a ventilation software controlling the vent opening level, opening sequence, based on the wind direction, and control interval according to the difference between ambient and set- up temperatures. The software included a beeper system alarming urgent cases, while a manager was remote from the greenhouse. A compatible hardware with the software was also developed by using a low-cost diffused DSP controller.

• Journal of Labour Economics
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• v.28 no.1
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• pp.29-60
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• 2005

This paper investigates how firms adjust wages, employment and hours in response to demand shifts. It focuses on rigidities and asymmetries in such adjustments. Major findings are as follows. First, wage adjustments are fairly small compared with worker adjustments. Second, wage adjustments are asymmetric with respect to sales growth: there is no responsiveness of wage growth when sales are declining, while adjustments are significantly positive when sales are rising. On the contrary, worker adjustments are symmetric with respect to demand shifts. Third, while workers are linearly adjusted to the sales growth, some nonlinearity is observed in the wage adjustment. Fourth, hours are generally nonresponsive to demand shocks. Finally, union firms cut wages rather than workers in the face of negative demand shocks.

• The Korean Journal of Financial Management
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• v.20 no.1
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• pp.125-162
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• 2003

This paper investigates the short- and long- run relationship among Korean, U.S. and Japanese construction indices. We conducted the Johansen's cointegration tests on the hypotheses that the construction indices of three countries we related in the long-run as well as in the short-run. The test results show that there exists no long-run relationship among three countrie's construction indices. In addition, the cointegrating relation did not exist for three countrie's stock market indices and five major Korean construction firms. It fumed out that the U.S. indices Granger-causes Japanese and Korean indices. This finding implies that there may exist international diversification benefit through forming a portfolio from these indices.