Earticle

In order to protect the head, baseball helmet must to have proper strength and to absorb the kinetic energy. The purposes of this study are to validate whether the helmet have the protecting ability or not. We performed three kinds of experiment to know about the this ability. To find out the limit of displacement at 4 points(front, rear, right side, and left side), the static load by magnetic dial gauges were used, and to validate the ability of absorption, drop tests were peformed from 0.5 and 1.0 meter. Futhermore, we calculated natural frequency of the helmets by the principle of Lissajous Diagram and we performed FEM(Finite Element Method) analysis. From the results of these experiments, we found that the displacement of helmet was largest at rear point and it was smallest at left-side point(ear-covered part). The ability of absorption was better at the left-side point than the other points.

In this study, an asymmetric lifting posture prediction model was developed, which was a three-dimensional model with 12 links and 23 degrees of freedom open kinematic chains. Although previous researchers have proposed biomechanical, psychophysical, or physiological measures as cost functions, for solving redundancy, they lack in accuracy in predicting actual lifting postures and most of them are confined to the two-dimensional model. To develop an asymmetric lifting posture prediction model, we used the resolved motion method for accurately simulating the lifting motion in a reasonable time. Furthermore, in solving the redundant problem of the human posture prediction, a moment weighted Joint Range Availability (JRA) was used as a cost function in order to consider dynamic lifting. However, it is known that the moment weighted JRA as a cost function predicted the lower extremity and L5/S1 joint motions better than the upper extremities, while the constant weighted JRA as a cost function predicted the latter better than the former. To compensate for this, we proposed a hybrid moment weighted JRA as a new cost function with moment weighted for only the lower extremity. In order to validate the proposed cost function, the predicted and real lifting postures for various lifting conditions were compared by using the root mean square(RMS) error. This hybrid JRA reduced RMS more than the previous cost functions. Therefore, it is concluded that the cost function of a hybrid moment weighted JRA can be used to predict three-dimensional lifting postures. To compare with the predicted trajectories and the real lifting movements, graphical validations were performed. The results also showed that the hybrid moment weighted cost function model was found to have generated the postures more similar to the real movements.

The small-and-medium sized construction sites are in weak state of safety management because of the variable working environments, the lack of safety techniques and the weak economic conditions, and industrial accidents of these sites were occupied 60％ of the total construction accidents. Recently, the safety engineer's number are not to be enough at the small-and-medium sized construction sites. Therefore, the safety engineer's works are addition to more and more. This paper is a development of the integrated program which using composition of construction safety management expenses. It is an management tool which helps to saving time of construction safety engineer. A method of development composition, to used Brain Storming for a place of meeting to construction safety management counselors.

We could not find researches for relationship between safety performance and business performance in comparison with other research areas. Then in this paper we suggest the hypotheses which can systematically explain the relationship between safety performance and business performance and analyze the effects of safety performance on business performance through regression analysis. In order to develop the regression model between safety performance and business performance, the previous studies both for environmental management and for quality management had been reviewed. We obtained the result that the number of the injured persons in occupational accident and the number of lost work day because of the accident which are selected as measurement for safety performance had an effect on business performance through empirical analysis both for large 43 enterprises and for small and medium 30 enterprises. Also we had found that the control variables selectively 3had an effect on business performance. Finally, we concluded that the safety performance had an effect on business performance both for large enterprise and for small and medium enterprise.

This Study is proposed solutions about operating and release of safety constructions and is researched about software safety estimation than hardware safety estimation. Also, preventing safety problems of Tower Crane operator and Construction workers as applying safety estimation program that developed at setup, operating, release stage after analyze problem patterns and causes.

Back pain is painful for people at a lower lumber(L4/L5 or L5/S1). It is experienced as a most frequent disaster 70％ of workers have suffered from back-pain. Especially, the occurrence rate of back pain for nurses is very high. Therefore, this study investigates female nurses who worked as a part of a medical cost management team, which mainly deal with the medical insurance in a general hospital at Seoul area. These nurses had different job tasks, which used computers for 50％ of their time, so it can be treated as VDT workers. As a first step of this project, a muscle fatigue was measured for these special VDT workers. First, survey for nurses was conducted to figure out what is a real problem of them. Second, to evaluate an experimental data, a medical cost management team was chosen for subjects. Areas of measurement were 3 places that were the trapezius (TR), the medial deltoid (MD), and the erector spine muscle (ES: L4/L5). These areas are most frequently used, so they were chosen for this study. Measurements were taken before work and after work. From these measurements, it was revealed that a fatigue really comes from their main VDT task excluding natural fatigue after work, so their work environment need to be corrected.

Today's environment of enterprise is changing. They have to face customer' demands with the right product, the right service and supply them at the right time. And also cut down logistics and inventory cost and bring up the profit as much as they can. This means the change of putting enterprise first in importance to putting customer first importance. therefore to correspond to customer's demand, shorting lead time is becoming a essential condition. The answer to this changes of environment is supply chain management. In the Supply chain, The ATP function doesn't only give customers to conformation of delivery. It can be used by the core function with ATP rule that can reconcile supplies and demands on the supply chain. Therefore We can be acquire the conformation about on the due date of supplier by using the ATP function of management about real and concurrent access on the supply chain, also decide the affect about product availability due to forecasting or customer's orders through the ATP. In this paper, It consolidates the necessity on a CTP and analyzes data which is concerned of ATP. Under the these environments, defines the ATP rule that can improve the customer value and data flow related the LTV(Life Time Value) and builds on a algorithm.

In this thesis presents line balancing problems of two-sided and mixed model assembly line widely used in practical fields using genetic algorithm for reducing throughput time, cost of tools and fixtures and improving flexibility of assembly lines. Two-sided and mixed model assembly line is a special type of production line where variety of product similar in product characteristics are assembled in both sides. This thesis proposes the genetic algorithm adequate to each step in tow-sided and mixed model assembly line with suitable presentation, individual, evaluation function, selection and genetic parameter. To confirm proposed genetic algorithm, we apply to increase the number of tasks in case study. And for evaluation the performance of proposed genetic algorithm, we compare to existing algorithm of one-sided and mixed model assembly line. The results show that the algorithm is outstanding in the problems with a larger number of stations or larger number of tasks.

Nowdays cyber education based on the internet is actively developed. But the management of the customers in the cyber education field is not enough. Then, in this paper, we provide the learner with the proposals of lectures to be extremely matched by analyzing the learning capacity and the greatest concern of him(her) using the methods of data mining, such as RFM, prediction, slickness, association rule, classification, and so on.

The marketing environment of recent security business has been changed as goods and service have been changed variously. Under this condition, the security corporations have been trying to have good relationship with customers and to have high gains as well. But the management of the customers in the bond marketing is not enough. Then, this paper suggests some methods to promote the CRM at bond brokerage in order to make profits in the security corporation. First, the customers will know the earning rate of the bond that they have and also they can analysis the difference selling the bond and keeping it until the due date. The developed bond management system analyzes customers' preference from questionaire which is responded by customers. It also can make customers actively sell and buy the bond through recommendations corresponding with customers' preference. Moreover, this paper suggests the video conference consulting system for close relationship with corporation and customers. We have tested this bond management system and we expect that this system activates the buying and selling of the bond that non-experts can easily invest bonds and the security corporations can increase profit.

For global electronic market, several market place standards are developing now. Though, a standard is different from others they are pursuing the same purpose of uniworld market. In this study, two standards(ebXML and UDDI) which are most strong enough to urge field engineers to consider the standards in making their products were focused. Additionally, the development priorities of ebXML which were viewed from field engineers were summarized. Finally, government actions required by field engineers to promote the development of global market place were summarized.

As the Internet spreads rapidly, the industrial structure is changing to a new paradigm. The previous EDI system was asked to be changed and WEB EDI, E-Mail EDI, FTP EDI etc. based on the internet have appeared. Recently, the XML/EDI which is based on XML documents has appeared. EDI system has to assure a safe exchange between senders and receivers. But, the internet has security problems because it uses a open TCP/IP protocol. In this paper, we will propose an XML/EDI system with XML Signature.

An Order Management System related to press die fabrication in automobile industry are developed in this research. This system is constructed by CORBA and XML to avoid disorder from data integration. Because CORBA can integrate diverse applications within distributed heterogeneous environments and XML can be made use of data exchange format, The developed system is available on almost any hardware platforms, operation system environments, and programming languages.

As the market and the organizations of an enterprise expand globally, the rapid and accurate communication gets more important for product manufacturing. The manufacturing information flow among the designers, the process planners and the shop floors is characterized and modelled. Its methods are constructed using distributed objects. Their introduction to the network-based CAPP system offers speed and safety for the system and makes the reconstruction and distribution of the application programs easy. The manufacturing processes are generated based on the feature information of a designed part, then the manufacturing resources are selected using the process planning logic which is implemented by distributed objects. The databases and distributed objects are integrated under the recent internet environments. The developed system makes it possible to manipulate and to transfer the process planning and manufacturing data everywhere in the world.

This paper presents an analytic method of quality function deployment(QFD) that is to maximize customer satisfaction subject to technical and economic sides in process design. We have used Wasserman's normalization method and the analytical hierarchy process(AHP) to determine the intensity of the relationship between customer requirements and process design attributes. This paper also shows cost-quality model the tradeoff between quality and cost as a linear programming(LP) with new constraints that have designated special process required allocating firstly. The cost-quality function deployment of piston ring is presented to illustrate the feasibility of such techniques.

A study to analyze and solve problems of multi wire installation duct experiment has presented in this paper. We have taken Taguchi's parameter design approach, specifically orthogonal array, and determined the optimal levels of the selected variables through analysis of the experimental results using S/N ratio.

Composites have wide applications in aerospace vehicles and automobiles because of the inherent flexibility in their design lot improved material properties. Composite tubes in particular, are potential candidates for their use as energy absorbing elements in crashworthiness applications due to their high specific energy absorbing capacity and the stroke efficiency. Their failure mechanism however is highly complicated and rather difficult to analyze. This includes fracture in fibers, in the matrix and in the fiber-matrix interface in tension, compression and shear. The purpose of this study is to investigate the energy absorption characteristics of Gr/E(Graphite/Epoxy) tubes on static and impact tests. The collapse characteristics and energy absorption of a variety of tubes have been examined. Changes in the lay-up which increased the modulus increased the energy absorption of the tubes. Based on the test results, the following remarks can be made: Among CA15, CA00 and CA90 curves the CA90 tube exhibits the highest crush load throughout the whole crush process, and max load increases as interlaminar number increase. Among all the tubes type CC90 has the largest specific crushing stress of 52.60 kJ/kg which is much larger than other tubes.

The polycrystalline CdS of large scale were grown by chemical pyrolysis deposition for Cu2 S/CdS heterojunction solar cells. For high quality CdS polycrystalline thin films, the chemical solution was deposited on indium tin oxide(ITO) glasses at the temperature of 500℃ for 15 second and annealed at 350℃ for 20 minute or 500℃ for 30 second. To fabricate high efficiency solar cells, optical and electrical properties, morphology by SEM and x-ray diffraction on polycrystalline CdS thin films were investigated. From the I-V characteristics of Cu2 S/CdS heterojunction, the open circuit voltage, Voc was 0.7 V and the short circuit current, Isc was 4.2 mA. We found that the fill factor(FF) was 0.5 and the efficiency was 2.5%.

Machinability improvement by the use of liquid nitrogen in cryogenic machining has been reported in various studies. This has been mostly attributed to the cooling effect of liquid nitrogen. However, No study has been found in discussion on whether liquid nitrogen possesses lubrication effect in cryogenic cutting. In machining tests, cryogenic machining reduced the force component in the feed direction, indicating that the chip slides on the tool rake face with lower friction. This study also found that the effectiveness of LN2 lubrication depends on the approach how LN2 is applied regarding cutting forces related.

This paper presents some indirect physical evidences indicating that reduced friction occurs in an economical cryogenic machining process, in which LN2 is applied selectively in well-controlled jets to the localized cutting zone. These evidences include cutting force components, tool wear rate and chip morphology. LN2 reduced the tool wear rate to a great extent and elongated the tool life up to four times compared to emulsion cooling. The friction reduction was further reflected in larger shear angle and less secondary deformation in the chip microstructures. This study also found that the effectiveness of LN2 lubrication depends on the approach how LN2 is applied.

A cutting fluid can improve machining quality and tool life by maintaining the tool toughness and by providing a lubrication effect to reduce the friction between the chip and tool interface. Although liquid nitrogen as an environmentally safe coolant has been widely recognized in cryogenic machining, its function as a lubricant is plausible due to its chemical inertness, physical volatility and low viscosity. Since a reduced friction is a direct witness of the lubrication effect from a tribological viewpoint, this paper presents an evaluation of the apparent friction coefficient on the tool-chip interface in cryogenic cutting operations to prove and characterize the lubricity of LN2 in cryogenic machining. The mathematical approaches have been formulated to derive the normal and frictional forces on the tool-chip interface for the oblique cutting tests.