But at present , there seem to be much deficiencies on the correctness and reliability of workflow and it can not meet the practical needs very well . in this paper , we introduce some transactional properties to workflow and put forward a nested workflow model with transactional characteristics . this model includes nested tasks and dependencies between the tasks , and it is provided with some atm properties such as relaxed isolation and atomicity . further more , we discuss the execution mechanism , system recovery and error handling of workflow on the base of the transactional characteristics . by defining consistency unit and execution atomic unit , we loosen the failure atomicity , serializability of concurrent worflow and isolation between tasks , thus , workflow meets the needs of the application semantics more flexiblly with high correctness and reliability 这个模型包含嵌套任务和任务间的依赖，并具有高级事务模型的一些属性，比如松散的隔离性和原子性。我们又进一步在这个模型的基础上利用这些事务性质提出了有关工作流的执行机制、系统恢复和错误处理等问题的解决方法。通过定义一致性单元和执行单元放松了事务的失败原子性、并发工作流的可串行化要求以及任务间的隔离性，使工作流在具有高可靠性和正确性的前提下更灵活地满足实际应用语义的要求。
Deferred global view maintenance can speed up the update transactions by shifting maintenance into a deferred transaction , but even strict two phase locking ( 2pl ) can not guarantee the serializable execution of transactions in this case . this paper develops a serializabitity theory base upon conflicts and serialization graphs in presence of deferred global view maintenance 由于延迟视图维护机制允许修改事务在全局视图没有进行相应的改动之前提交，有暂时的数据不一致情况出现，在这种情况下，即使严格的zpl协议也不能保证全局事务的可串行化执行。
Conceptually , the deployer takes binary code for the gbeans in the form of code modules and metadata information in the form of xml deployment plans , and then processes them to create a serialized image of the configuration . this configuration image is then persisted to a configuration store 总体上来讲，开发人员可以获取gbeans的二进制代码（以代码模块的形式）和元数据信息（以xml部署计划的形式） ，然后对它们进行处理，以创建串行化的配置映像，此配置映像然后被持久存储到配置存储区。
Traditional concurrency control methods can ’ t be well applied to resolve these problems in a loosely - coupled environment . the application constructor has no central control on resources provided by autonomous business entities . since the business process is long - running , the providers may not be willing to lock resources exclusively for such long period , and serialization by locking resource will raise serious scalability issues 传统的并发控制方法并不完全适应web服务环境下松耦合应用集成的特点,主要表现在:资源是自治的,无法对来自不同提供者的资源进行集中控制;业务流程的复杂性使流程的执行跨越较长的时间,一方面资源提供者可能不愿意长时间地锁定资源,另一方面运用加锁等串行化方法将导致并发度降低,严重影响利用效率。
Further , to avoid serialization problems , the file system is not responsible for serializing this access - the paging file belongs to the vm system , and the vm system is responsible for serializing access to this file ( this eliminates some of the re - entrant locking problems that occur with general file access ) 进一步，为了避免串行化问题，文件系统不负责将访问串行化页面调度文件属于虚拟内存系统，而虚拟内存系统负责把对这个文件的访问串行化（这消除了出现在常规文件访问中的重入锁定问题） 。
Security constraints are consistent by modifying security constraint definition , and an effective classification assignment algorithm is given in this paper . we analyze the problem of inference channel and give solution to solve the problem during database analysis and design period . by analyzing the problems resulting from extending single - level transactions to multilevel transactions , we also give a multilevel secure transaction schedule algorithm based multiversion snapshot graph 本文提出采用主从结构表的方法对blp模型加以改造，使得改造后的blp模型具有较高的可用性和安全性；通过修改安全约束的定义，使得安全约束之间始终是协调的，并给出一种高效的密级分配算法；讨论了推理通道问题，给出了在数据库分析、设计等阶段可以采用的对策；分析了事务从传统的单级扩展到多级面临的众多难题，给出了一种基于多版本串行化图的事务调度算法；根据上述理论，开发了一个多级安全数据库管理系统的原型系统。
This card largely depends on three integrate chips to fulfill its function : 1 ) nic control main chip , corresponding the mac sublayer of ethernet , to realize csma / cd media access protocol , manage the sending and receiving buffers integrated on the chip and provide motherboard pci interface . 2 ) serdes ( serializing and deserializing ) chip , corresponding pcs and pma sublayers in ethernet , mainly to complete 8b / 10b coding and convert 10 bits parallel data to serial data , and convert them again at the receiving end . 3 ) fibre transceiver unit , completing light - electrical conversion of seri 该网卡主要由3块集成的芯片完成其功能，分别是i ）网络控制主芯片，对应于以太网的mac子层，主要完成csmaicd介质访问协议，管理片上集成的发送和接收缓冲区，并提供和主板p0总线的接口： b ） s rd s （串行解串行化器）芯片，对应于以太同的pcs和pma子层，主要完成sb lob编码并将10位并行的数据转换为串行数据，在接收端完成相反的功能：涌）光纤收发器，完成串行数据的光电转换功能。
