In order to remove the inefficient cost occurred among companies, the cooperation among companies are required. The single vendor-single buyer integrated model is often studied for that purpose. Buyer’s demand follows normal distribution, and vendor’s inventory policy use a continuous inventory review policy. If buyer places order, then vendor begins to make products and transfer those products to the buyer several times. In real situation, the size of company’s warehouse is restricted, space limit constraint is considered. There are three approaches for the single vendor-single buyer integrated model with space limit: equal batch shipment approach, increasing batch shipment approach, and mixed approach. In this paper, these approaches are compared one another and we discuss about the advantages and disadvantages of these approaches.

This study aims to investigate the effect of DDL on English lexico-grammar learning by Korean middle school students with respect to the types of learning approach (deductive vs. inductive DDL), the student’s level of English (low vs. high level), and the complexity of lexico-grammar items (simple vs. complex). A total of five experimental lessons were given to 36 students divided into two groups: one group received the lessons through the deductive DDL approach and the other group through the inductive DDL approach. The study found that both inductive and deductive DDL were effective in the learning of English lexico-grammar by the Korean middle school students. However, deductive DDL was more effective for the high level students, while inductive DDL was more appropriate for low level students. In addition, both deductive and inductive DDL were effective for teaching simple lexico-grammar items, but deductive DDL was more effective for teaching complex ones. Most of the participants showed positive responses about DDL and expressed a view that they were able to learn the meanings as well as the forms of target lexico-grammar items.

Unlike most researches that focus on single manufacturer or single buyer, this research studies the cooperation policy for two participants of supply chain such as single vendor and single buyer. Especially, this paper deals with single vendor-single buyer integrated-production inventory problem. If the buyer orders products, then the vendor will start to make products and then the products will be shipped from the vendor to the buyer many times. The buyer is supposed to order again when the buyer’s inventory level hits reorder point during the last shipment and this cycle keeps repeated. The buyer uses continuous review inventory policy and customer’s demand is assumed to be probabilistic. The contribution of this paper is to present a mixed approach and derive its cost function. The existing policy assumes that the size of shipping batch from single vendor to single buyer is increasing, called Type 1, or constant, called Type 2. In mixed approach, the size of shipping batch is increasing at the beginning part of the cycle, and then its size is constant at the ending part of the cycle. The number of shipping for Type 1 and Type 2 in a cycle in mixed approach is determined to minimize total cost. The relationship between parameters, for example, the holding cost per product, the set up cost per order, and the shortage cost per item and decision variables such as order quantity, safety factor, the number of shipments, and shipment increasing factor is figured out via sensitivity analysis. Finally, it is statistically proved that the mixed approach is superior to the existing approaches.

This paper considers one vendor-one buyer integrated-production inventory problem. If the buyer orders products, then the vendor will start to make products and then the products will be shipped from the vendor to the buyer many times. The buyer is supposed to order again when the buyer’s inventory level hits reorder point during the last shipment and this cycle keeps repeated. Buyer uses continuous review inventory policy and customer’s demand is assumed to be probabilistic. The contribution of this paper is to develop a new approach for one-vendor-one-buyer integrated production-inventory problem.

This paper is concerned with the single vendor single buyer integrated production inventory problem. To make this problem more practical, space restriction and lead time proportional to lot size are considered. Since the space for the inventory is limited in most practical inventory system, the space restriction for the inventory of a vendor and a buyer is considered. As product’s quantity to be manufactured by the vendor is increased, the lead time for the order is usually increased. Therefore, lead time for the product is proportional to the order quantity by the buyer. Demand is assumed to be stochastic and the continuous review inventory policy is used by the buyer. If the buyer places an order, then the vendor will start to manufacture products and the products will be transferred to the buyer with equal shipments many times. The mathematical formulation with space restriction for the inventory of a vendor and a buyer is suggested in this paper. This problem is constrained nonlinear integer programming problem. Order quantity, reorder points for the buyer, and the number of shipments are required to be determined. A Lagrangian relaxation approach, a popular solution method for constrained problem, is developed to find lower bound of this problem. Since a Lagrangian relaxation approach cannot guarantee the feasible solution, the solution method based on the Lagrangian relaxation approach is proposed to provide with a good feasible solution. Total costs by the proposed method are pretty close to those by the Lagrangian relaxation approach. Sensitivity analysis for space restriction for the vendor and the buyer is done to figure out the relationships between parameters.

The single vendor single buyer integrated production inventory problem with lead time proportional to lot size and space restriction is studied. Demand is assumed to be stochastic and the continuous review inventory policy is used for the buyer. If the buyer places an order with lots of products, then the vendor will produce lots of products and the products will be transferred to the buyer with equal shipments many times. Mathematical model for this problem is defined and a Lagrangian relaxation approach is developed.

With an effort to verify the involvement load hypothesis, this study investigates the effects of three different vocabulary learning tasks - reading, filling in blanks, and sentence writing - on learners' short and long term memory when they are provided with the theoretically identical level of involvement tasks. It is also to examine whether there are any differences of learning effects between input and output vocabulary learning tasks. The experiments were conducted with 86 Korean middle school students grouped by three different task types. Pre-/post-tests and delayed tests were administered and analyzed. It was found that three vocabulary tasks with theoretically identical levels of involvement do not have the same learning effects: the involvement load hypothesis was not completely proved in the case of Korean students' vocabulary learning. The findings implied that (i) the difference of vocabulary learning tasks should be considered even though they have the same involvement load; (ii) given that EFL students learn new words in a limited amount of time in class, the reading task using a dictionary is found to be very helpful; and (iii) it is important to study target vocabulary repeatedly during class and to expose the vocabulary with different tasks to enhance students' retention of the newly learned vocabulary.

As order quantity is increased, the ordering cost per item will be cheaper due to saving of transportation and material handling costs. In this paper, two realistic assumptions such as quantity discount and budget limit are considered. Quantity discount means that all units in the order will be discounted according to the predetermined order levels. Budget limit represents that the costs for inventory investments are bounded. This paper develops a Lagrangian relaxation approach for a continuous review inventory model with a budget constraint and quantity discounts. Computational results indicate that the proposed approach provides a good solution. Sensitivity analysis is done to get some insights on budget limit and quantity discount. As budget limit or the amount of discount according to order quantity is increased, order quantity is increased, whereas reorder point is not always increased.

The modular assembly system can make it possible for the variety of products to be assembled in a short lead time. In this system, necessary components are assembled to optional components tailor to customers’ orders. Budget for inventory investments composed of inventory and purchasing costs are practically limited and the purchasing cost is often paid when an order is arrived. Service cost is assumed to be proportional to service level and it is included in budget constraint. We develop a heuristic procedure to find a good solution for a continuous review inventory system of the modular assembly system with a budget constraint. A regression analysis using a quadratic function based on the exponential function is applied to the cumulative density function of a normal distribution. With the regression result, an efficient heuristics is proposed by using an approximation for some complex functions that are composed of exponential functions only. A simple problem is introduced to illustrate the proposed heuristics.

We develop an optimization algorithm for a periodic review inventory system under a stochastic budget constraint. While most conventional studies on the periodic review inventory system consider a simple budget limit in terms of the inventory investment being less than a fixed budget, this study adopts more realistic assumption in that purchasing costs are paid at the time an order is arrived. Therefore, probability is employed to express the budget constraint. That is, the probability of total inventory investment to be less than budget must be greater than a certain value assuming that purchasing costs are paid at the time an order is arrived. We express the budget constraint in terms of the Lagrange multiplier and suggest a numerical method to obtain optional values of the cycle time and the safety factor to the system. We also perform the sensitivity analysis in order to investigate the dependence of important quantities on the budget constraint. We find that, as the amount of budget increases, the cycle time and the average inventory level increase, whereas the Lagrange multiplier decreases. In addition, as budget increases, the safety factor increases and reaches to a certain level. In particular, we derive the condition for the maximum safety factor.

In this paper, we develop an efficient approach to solve a continuous review inventory system with a budget constraint when the semi-finished product and optional components are required to be assembled. We are, in particular, interested in a budget constraint that includes a service level. The service cost, such as labor and facility costs, tends to increase as the service level increase, and it makes the problem difficult to solve. Assuming that the reorder point for a semi-finished product is given, we show that the order quantity for the semi-finished product and the order quantity and reorder point for optional components can be determined by minimizing the total cost that includes setup cost, inventory holding cost, and shortage cost. The performance of the proposed approach is tested by numerical examples. By using sensitivity analysis, we conclude that, as the reorder point for semi-finished product increases, the order quantity for semi-finished product increases, whereas the order quantity and reorder point of optional components decreases.

If service level is increased, then service cost such as labor cost and facility cost will be increased. This service cost is included in the budget constraint in this paper. This service cost makes the problem difficult to solve. The purpose of this research is to develop an efficient approach for a continuous review inventory system with budget constraint when the semi-finished product and optional components are required to be assembled. Assuming that the reorder point for semi-finished product is given, order quantity for semi-finished product and order quantity and reorder point will be determined to minimize total cost that includes setup cost, inventory holding cost, and shortage cost. The performance of the proposed approach is checked by using an example.

This paper deals with a centralized warehouse problem with multi-item and capacity constraint. The objective of this paper is to decide the number and location of centralized warehouses and determineorder quantity (Q), reorder point (r) of each centralized warehouse to minimize holding, setup, penalty, and transportation costs. Each centralized warehouse uses continuous review in- ventory policy and its budget is limited. A SA (Simulated Annealing) approach is developed and its performance is tested by using some computational experiments.

Inventory centralization for a number of stores may reduce inventory costs by establishing and maintaining a central ordering and distribution point. In this study, a centralized warehouse problem with multi-item and capacity constraint is considered. The objective of this study is to develop a methodology to decide the number and location of centralized warehouses and determine order quantity(Q), reorder point(r) of each centralized warehouse to minimize holding, setup, penalty, and transportation costs. In this problem, each centralized warehouse uses continuous review inventory policy and its budget is limited. A SA(Simulated Annealing) approach for this problem is developed.

In General, the surface roughness of turning is depends on cutting condition which are cutting speed, depth of cut, and feed, etc. This study was carried out to presume for mutual relation of turning condition to get optimum surface roughness and experimental equation by variance and multi regression analysis As the result, multiple correlation coefficient was calculated 97%, the coefficient of determination (R2) was calculated 95% and the adjusted coefficient was calculated 97% by multiple regression analysis So, the formula was made by this multiple regression analysis is reliable.

해양사고 중에서 인적요소(Human Factors)에 의한 사고가 80% 이상인 것으로 보고되고 있다. 인적요소는 원인과 결과 사이의 인과관계가 대단히 복잡하기 때문에 이를 분석 및 평가하기 어렵다. 본 연구에서는 다양한 문헌에 나타난 인적요소 식별과, 분석 및 평가 기법을 살펴보고, 최적의 기법도출에 필요한 위기요소의 사전식별과 연구접근 방법을 고찰하고자 한다. 연구결과, 국내외적으로 인적요소의 효과적인 관리체계와 분석 및 평가 연구가 미흡함