交易、服务行业的六西格玛工具简介.ppt

Time as a Process Parameter时间是一个过程参数 Time, as a metric, may be categorized as: 时间作为一个测量指标，可以分为以下三种： Access Time the length of time between the first customer contact until success 进入时间：从第一次接触客户到最后成交的时间 (Average time a unit spends in the system, Ws) Queuing Time Waiting time in terms of the length of the queue 排列时间：根据队列的长度得出的等候时间 (Average time a unit spends waiting in a queue, Wq) Action Time the interval between taking the “order” and providing the service requested. 行动时间：从接受“订单”到提供所要求的服务的时间 (Average time spent being serviced, Wa = Ws – Wq) A Simple Queuing System一个简单的排队系统 Process or Service 过程或服务 “Customer” Arrives “客户”到达 “Customer” Leaves “客户”离开 Characteristics of a Waiting Line等候队列的特点 Queue discipline is the method in which a new arrival moves into the process or service 排队纪律是新到者进入过程或服务的方法 FIFO - first-in, first-out 先进先出 LIFO - Last-in, first-out 后进先出 Pre-assigned priority 预先分配的优先权 Characteristics of a Waiting Line等候队列的特点 Service time can be modeled by the negative exponential probability distribution 服务时间能够根据负指数概率分布推算出 Single server or several 单渠道或多渠道 The transaction rate (service rate) must be faster than the arrival rate. Arrival Rate Service Rate 服务率一定要高过到达率 Classifying Queuing Systems排队系统分类 System Characteristics 系统特点 There are numerous queuing models from which an analyst can choose. Success depends on choosing the correct model. Model choice is affected by the characteristics of the system being investigated. 对于一个分析员来说，可供选择的排队模式非常多，而成功与否往往就取决于是否选择正确的模式。模式的选择受系统的特点的影响 Classifying Queuing Systems排队系统分类 The main characteristics are: 主要特点如下 Population source 客户来源 Number of servers (channels) 服务渠道的数量 Arrival and service patterns 到达和服务形式 Queue discipline (order of service) 排队原则 A Simple Queuing System一个简单的排队系统 Calling Population 需要服务的客户 Arrivals 到达 Waiting Line 等候队列 Process or Service 过程或服务 Exit 离开 Line too long? Customer never enters queue 队列过长？客户 不进入队列 Line too long? Customer abandons queue 队列过长？客户 离开队列 Arrival