• 대한토목학회논문집
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• 제31권5D호
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• pp.719-726
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• 2011

정부에서는 최저가 낙찰제도의 무리한 저가투찰을 방지하기 위해 입찰가격 적정성 심사기준 등을 강화하고 있으나, 낙찰가율이 저하되는 근본적인 문제점이 여전히 상존하고 있다. 본 연구에서는 최저가낙찰제도의 입찰금액 적정성 심사기준 문제점을 분석하였으며, 그 결과 발주기관의 기초금액 결정요소의 제한적 공개, 5% 초과분 구분공종의 비율, 부적정공종의 제한적인 심사항목 등이 낮은 낙찰가율을 형성하는 주요 요인으로 파악하였다. 이에 본 연구에서는 기존의 입찰금액의 적정성 심사 절차상의 문제점을 개선 할 수 있는 방법을 제안하고, 적정낙찰가율 범위에서 낙찰자를 선정할 수 있는 입찰금액 적정성 심사 기준을 보완한 프로세스 모형을 제시하며, 기존 발주사례를 통하여 적정성을 검증하고 있다.

• 자원ㆍ환경경제연구
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• 제23권1호
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• pp.43-65
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• 2014

본 논문에서는 국내 제조업 가운데 전력 사용량이 상대적으로 많은 화합물 및 화학제품 산업을 대상으로 암묵 (shadow) 비용함수를 사용하여 전력 등의 투입요소 간 효율적 배분 여부를 검증하고 전력의 적정수준 대비 과잉 투입 규모를 조사한다. 기업의 비용최소화 달성을 전제로 각 투입요소에 대한 수요의 가격탄력성을 추정하여 전력요금 인상에 대한 각 요소 수요의 파급효과를 모의실험을 통하여 분석한다. 또한 공급관계식을 비용함수의 방정식체계에 추가하여 동시 추정함으로써 전력요금 10% 인상 시 물가지수에 미치는 영향을 분석한다. 실증분석 결과, 1982-2006년 기간 동안 '투입요소 간 효율적 배분 달성'의 귀무가설은 기각되었으며, 전력은 적정수준 대비 평균적으로 매년 약 98% 과잉 사용되고 있는 것으로 나타났다. 다른 요인들이 불변하다면 전력요금이 10% 인상될 경우 전력 수요는 약 11.4% 감소하였으며, 공급가격은 평균적으로 0.08% 하락하는 것으로 나타났다.

• 한국컴퓨터정보학회논문지
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• 제28권8호
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• pp.67-75
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• 2023

주가 예측은 금융시장에서 중요하게 다뤄지고 있는 주제이지만 영향을 미칠 수 있는 다수의 요소들로 인해 어려운 주제로 고려되고 있다. 본 논문에서는 시계열 예측 모델 (LSTM, GRU)과 데이터의 시간적 의존성을 고려하지 않는 비 시계열 예측 모델 (RF, SVR, KNN, LGBM)을 주가 예측에 적용하여 성능을 비교하고 분석하였다. 또한 주가 데이터와 기술적 분석 보조지표, 재무제표 지표, 매수매도 지표, 공매도, 외국인 지표 등 다양한 데이터를 조합 및 활용하여 최적의 예측 요소를 찾아내고 업종별로 주가 예측에 영향을 미치는 주요 요소들을 분석했다. 하이퍼파라미터 최적화 과정을 통해 알고리즘별 예측 성능을 향상 시키는 과정도 진행하여 성능에 영향을 주는 요인을 분석하였다. 변수 선택과 하이퍼 파라미터 최적화 과정을 거친 결과, 시계열 예측 알고리즘인 GRU, 그리고 LSTM+GRU의 예측 정확도가 가장 높은 것으로 나타났다.

• Ocean and Polar Research
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• 제40권4호
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• pp.237-247
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• 2018

This study aims to estimate optimal harvests, fishing efforts, and stock levels of hairtail harvested by the large pair bottom trawl, the large otter trawl, the large purse seine, the offshore long line, and the offshore angling fisheries by using the surplus production models and the current value Hamiltonian method. Processes of this study are as follows. First of all, this study estimates the standardized fishing efforts regarding the harvesting of the hairtail by the above five fishing gears based on the general linear model developed by Gavaris. Secondly, this study estimates environmental carrying capacity (k), intrinsic growth rate (r), and catchability coefficient (q) by applying the Clarke Yoshimoto Pooley (CY&P) model among various surplus production models. Thirdly, this study estimates the optimal harvests, fishing efforts, and stock levels regarding the hairtail by the current value Hamiltonian method, including the average landing price, the average unit cost, and the social discount rate. Finally, this study attempts a sensitivity analysis to figure out changes in optimal harvests, fishing efforts, and stock levels due to changes in the average landing price and the average unit cost. As results induced by the current value Hamiltonian method, the optimal harvests, fishing efforts, and stock levels regarding the hairtail caught by several fishing gears were estimated as 33,133 tons, 901,080 horse power, and 79,877 tons, respectively. In addition, from the results of the sensitivity analysis, first of all, if the average landing price of the hairtail constantly increases, the optimal harvests of it increase at a decreasing rate, and then harvests finally slightly decrease as a result of decreases in stock levels. Secondly, if the average unit cost of fishing efforts continuously increases, the optimal fishing efforts decreases, but optimal stock levels increase. Optimal harvests start climbing and then decrease continuously due to increases in the average unit cost. In summary, this study suggests that the optimal harvests (33,133 tons) were larger than actual harvests (25,133 tons), but the optimal fishing efforts (901,080 horse power) were much less than estimated standardized fishing efforts (1,277,284 horse power), corresponding to the average of the recent three years (2014-2016). This result implies that the hairtail has been inefficiently harvested and recently overfished due to excessive fishing efforts. Efficient management and conservation policies on stock levels need to be urgently implemented. Some appropriate strategies would be to include the hairtail in the Korean TAC species or to extend the closed fishing season for this species.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2007년도 추계학술대회 및 정기총회
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• pp.3-6
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• 2007

In the traditional inventory problem, market parameters such as demand and selling price are exogenous. But incorporating these factors into the model can provide an opportunity for increasing the total profit. So we investigate the joint price-inventory policy in a supply chain consisting of a single retailer and a single manufacturer. Demand at the retailer depends on the retail price. The retailer and the manufacturer cooperate closely each other to maximize overall profit of the supply chain. The mathematical model is presented and the solution procedure is developed in order to jointly determine the optimal policy including the retail price, the production lot sizes, and the delivery frequency from the manufacturer to the retailer.

• Journal of information and communication convergence engineering
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• 제13권2호
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• pp.86-96
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• 2015

In mobile communication, mobile services [MSs] (e.g., phone calls, short/multimedia messages, and Internet data) incur a cost to both mobile users (MUs) and mobile service providers (MSPs). The proposed model MobPrice consists of dynamic data pricing schemes for mobile communication in order to achieve optimal usage of MSs at minimal prices. MobPrice inspires MUs to subscribe MSs with flexibility of data sharing and intra-peer exchanges, thereby reducing overall cost. The main contributions of MobPrice are three-fold. First, it proposes a novel k-level data-pricing (kDP) scheme for MSs. Second, it extends the kDP scheme with the notion of service-sharing-based pricing schemes to a collaborative peer-to-peer data-pricing (pDP) scheme and a cluster-based data-pricing (cDP) scheme to incorporate the notion of 'cluster' (made up of two or more MUs) in mobile communication. Third, our performance study shows that the proposed schemes are indeed effective in maximizing MS subscriptions and minimizing MS's price/user.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전력기술부문
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• pp.107-110
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• 2004

This paper provides calculation of nodal price using voltage variables on Power System Operation. In this method we show deriving Shadow Price from state variables in Optimal condition. and we presented a new spliting method using voltage variables for zonal price. The proposed method is applied to IEEE-30 and results shows the effectiveness of the method.

• East Asian Economic Review
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• 제24권3호
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• pp.237-252
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• 2020

This paper characterizes the optimal reciprocal trade policy in the environment of Melitz (2003) with firm productivity heterogeneity. In particular, without making parametric assumptions on firm productivity distribution, this paper derives the optimal degree of reciprocal tariff reductions that maximize the world welfare. A reciprocal import subsidy raises the industry productivity, lowering aggregate price; a reciprocal import tariff helps correct the markup distortion, increasing nominal income. With all the conflicting effects of import tariffs on welfare considered, the optimal degree of reciprocity in multilateral tariff reduction is shown to be free trade.

• International Journal of Advanced Culture Technology
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• 제8권1호
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• pp.62-70
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• 2020

As an effective means of price discrimination, some suppliers offer trade credit to the distributors in order to stimulate the demand for the product they produce. The availability of the delay in payments from the supplier enables discount of the distributor's selling price from a wider range of the price option in anticipation of increased customer's demand. Since the distributor's lot-size is affected by the demand for the customer, the distributor's lot-size and the selling price determination problem is interdependent and must be solved at the same time. Also, in many common business transactions, the distributor pays the shipping cost for the order and hence, the distributor's ordering cost consists of a fixed ordering cost and the shipping cost that depend on the order quantity. In this regard, we deal with the joint lot-size and price determination problem when the supplier allows delay in payments for an order of a product. The positive effects of credit transactions can be integrated into the EOQ (economic order quantity) model through the consideration of retailing situations, where the customer's demand is a function of the distributor's selling price. It is also assumed that the distributor's order cost consists of a fixed ordering cost and the variable shipping cost. We formulate the distributor's mathematical model from which the solution algorithm is derived based on properties of an optimal solution. A numerical example is presented to illustrate the algorithm developed.

• 자원ㆍ환경경제연구
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• 제25권1호
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• pp.113-140
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• 2016

한 가지의 용량가격만으로는 발전용량 설비투자에 대한 안정적 보상과 시장 기능 유지라는 두 가지 목표를 동시에 달성하기 힘들다. 본 논문은 이런 한계를 극복할 수 있도록 복수의 용량가격을 도입하여 용량가격의 비중을 높이면서 동시에 시장 기능을 유지할 수 있는 이원적 용량가격 제도를 제안한다. 즉, 현재 가스터빈 발전기를 기준으로 하면서 행정적으로 결정되는 용량가격을 그대로 유지하면서, 동시에 LNG복합발전기를 대상으로 한 제2의 용량가격을 도입한다. 이 용량요금은 더 낮은 에너지 가격 상한의 적용을 받으며, 상이한 전원들 사이의 대체관계를 고려한 수요와 용량공급 상황을 반영하도록 설계함으로써 시장 기능을 유지하게 한다.