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Position:IcFull.com » IC Electronic information » Category: A

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An adaptive solution HCI

In Electronic Infomation Category: A | on April 13,2011

Abstract: In embedded systems engineering and ADM690AAR datasheet and field construction practices, to address resource degradation due to the embedded system due to the complexity of human-computer interaction and ADM690AAR price and uncertainty, from the adaptive perspective, analysis of embedded systems in human-computer interface (HCI) can be adaptive needs, should provide a HCI for adaptive resource degradation solution, so the interactive features of embedded devices for the study, a detailed description of the HCI model for embedded devices and ADM690AAR suppliers and memory The establishment of the structure, and gives practical significance of the HCI with an adaptive strategy, the last instance to validate a project. We can see from the examples, project development for embedded systems provides a feasible solution.

Embedded system is application-centric, computer technology, hardware and software can be cut for application of the function, reliability, cost, size, power requirements are strictly dedicated computer system, which works practice is gradually rise to the concern of researchers, in the actual project there are many factors to consider, such as the microprocessors power consumption, device reliability, resistance to harsh environmental capacity of equipment, human-computer interface (HCI), on-site communications and so on. HCI engineering for embedded systems is an important issue. Because some embedded system development complexity and uncertainty in the implementation of the project, resulting in a rigid embedded systems trends HCI, which proposes a solution to adaptive thinking is necessary.

1 embedded project HCI

Graphical user interface is the mainstream of the current user interface. HCI is to determine whether the kind of embedded computer systems is an important factor. The main function of embedded systems rely on human-computer interaction input and output devices and corresponding software to achieve synergy. The equipment used for human-computer interaction are the keyboard, display, and a variety of pattern recognition equipment. Embedded systems because of their special human-computer interaction differ with the PC, most embedded systems are display screen and keyboard, or positioning devices with touch screen components. For users, the need to use the action button or touch screen to tell the system to output in accordance with the intent of the majority of embedded systems have a HCI system for users. The problem is interaction in engineering design, interface designers often will link the resources and systems, making the interface design is not independent of the system resources. Software design is bound to a large extent limited hardware resources. In practice, the usual approach is based on the existing conditions of the temporary organization of a hardware data structure, the series string value "string" together can be achieved between each jump. Description of an interactive snapshot of the node generally require several components: 1) the state of an enumerated; 2) shows a constant state value; 3) the precursor state; 4) the successor state. Id may also need to include node identification and other supporting information. Obviously, this is a static method to generate a menu object, code readability and strong, but each part of the interdependent, coding and debugging more complicated, you need all parts of the designers are very clear. The biggest problem is the limited scalability, the increase in the size of the follow-up have been affected. Engineering practice, and implied needs of the users needs are often complex and uncertain.

Purpose of this study is to establish a set of applications to adapt to the complexity and uncertainty of the realization of programs for the development of embedded systems to provide a follow-up of Solutions Engineering.

2 can be adapted to embedded HCI

HCI is adaptable computing environment according to the system or application scenarios for the interface with regulation. Can be further divided into passive adaptation and proactive adaptation (or adaptive).

Adaptability in embedded systems development in HCI has become increasingly urgent demands. Usually the demand comes from two aspects, one is the user needs to change; and a system implementation of environmental change. Starting from these two kinds of factors, according to the behavior of adaptive embedded HCI can be adaptive from the following two aspects of:

Adaptability refers to the so-called static static configuration associated with the system adaptable, adaptive behavior usually occurs between the 2nd boot. This adaptation is usually outside the demand, such as user requirements change, design changes. In engineering, there are often iterative adaptation, so adaptability is still a very practical significance needs. The implementation must be adaptive to the use of non-volatile memory used to store the changed definitions and configuration parameters, making the successful completion of adaptive behavior.

Dynamic adaptability refers to the system is running, you can change the environment based on online adaptive changes, that is pervasive environment changes. Pervasive devices are usually migrate in the use of the environment, causing changes in the mandatory environmental parameters, the system will generate conflicts HCI and the environment, so universal and its application in adaptive adjustment is necessary. System state based on the collected information to determine whether the HCI and system configuration synchronization, relying on algorithms to achieve real-time adaptive correction system configuration. Adaptive characteristics of pervasive environments is dynamic, there is a conflict only when it is made universal adjustment, the design must be considered for matching.

3 list based on the embedded multi-HCI

3.1 Model

Multiple sequential list structure data in the organization have a faster search speed, the following list gives a model based on multiple, each node fanout of 4, pointing to the upper node, the lower nodes, left and right neighbors node, fan is not limited. Each node has a two-way between adjacent nodes connected and each node can be expanded nodes tape.

Model from the functional sense is a hierarchy, from the data model point of view is the network structure, allowing no more than one parent node and a node can have more than one parent. Each node number is not fixed, visible changes in the actual situation. Each layer is a two-way closed loop, horizontal two-way traverse. Layers between the eldest son of the node from the parent node and two-way connection. Parent node is the one to one contact layer nodes pair, from the parent node into the sub-layer stop when the eldest son of the node; sub-layer nodes is many to one link of the parent node, which means from each child node can be traced back to the parent node. Switch to the child by the parent level must be the eldest son of each node traversed, then followed by the eldest son of horizontal loop through the node, sub-layer switch to the parent are more flexible, each child node can reach its parent node.

3.2 program to achieve

3.2.1 Memory design

Node should have four domains, in addition to the identity label things, for at least a parent node pointer points to the upper field, point to the lower sub-node pointer field, and point to the same level of left and right pointer fields brother.

Figure 1 is a simple HCI structure, from a functional point of view, it is divided into 5 layers, the first layer has five nodes form a closed loop entry, the second layer is the first layer of closed-loop child nodes of the first node group, the second child node group node group and the Son. It goes on a total of 5 layers, the highest position of the nodes in its parent pointer is empty, the son of the lowest position of the node pointer is null.


HCI Figure 1 A simple diagram

3.2.2 Class Design

Model definition shown in Figure 2 according to the class object. Shown on the left menu is a basic node class, in addition to several nodes in the model mentioned in the pointer, it has added several related attribute domain, Id used to identify the node status, displayValue used to store the display of the menu title, boolean editable members indicate whether the current node can be edited to add a ptr_functiON field also used to point to a performance function, the function to complete the node receiving the message to determine what to do after work.


Figure 2 menu node agent class definition and menu class definition

In the node class also defines several members of the method name associated with the private property line with the naming of OOP requirements, are using the Get-Set prefix rules. In addition to the methods for the properties of several members, but also introduces several other members of the method, CoUp execution jump to the parent node, CoDown implementation of the eldest son of the node to jump, CoLeft and GoRight responsible neighbors to the left and jump.

Independence and resources from the software design considerations, proposed the concept of an interface agent, interface agent is based on event-driven, interface with the environment in an intermediate object. External events to receive the message identified by the agency, which would call the interface elements on the interface to make changes. Shown in Figure 2, the upper part of the definition of the right is the menu proxy class MenuManageAgent. Class object is used as a menu system of the vehicle interaction with the outside world, it is a pointer to the head of the Records menu, the menu system size and the overall state of the menu; initialize the menu structure, create a menu system and accepting foreign message on behalf of the menu , and the message to identify and make a reasonable response. Figure 2 lower right is the definition of the external message. The message list can be expanded and modified according to the actual situation.

4 embedded HCIs adaptability to achieve

Static can be adapted to the implementation is based on the subjective intent of the user. This process emphasizes human-computer interaction, so the users job content is important, generally implemented as a static input parameters can be adaptive. The technical details of implementation is relatively simple. In the algorithm design, adaptability to achieve this kind of work continued to focus on content management, user interaction, from the users "interactive content" function can be integrated system interface "change gap", and then derive the specific parameters of the system HCI set changes.

Shown in Figure 3, the device can use the environment to adapt to the dynamic state detection system start, this is a cyclical behavior, frequency based system in real time on the HCI requirements. State detection system should include the work of several parts: 1) There should be a means of monitoring environmental parameters, such as sensors, access signals; 2) should be based on specific algorithms to determine this conflict, including differences in access, scale of development. State test results is whether there are contradictions output, if the case appears contradictory, decision analysis needs to be done, and its main task is whether the existing conditions based on the system can adapt dynamically, such as has reached a critical state to loss of such a possibility. So here comes to the management of system resources scheduling. The next step is to adapt to the situation in the dynamic, the dynamic adaptation strategies are given the right of HCI to adjust the system to achieve universal environment can dynamically adapt to the purpose.


Figure 3, the adaptive algorithm for dynamic processes

5 Application

5.1 Project Description

We used a series of projects in the following program structure HCI menu system. Embedded in a company developing a data acquisition products, the product code and data stored in two separate Flash chips, the outside world through the acquisition of analog and digital output after its treatment. Products, man-machine interface using keypad, LED digital tube, calculation control unit Freescale Semiconductor Coldfire V2 series of microprocessors, the CPU core based on variable-length RISC processor with 32-bit address lines and data lines and integrated debug module, MAC / eMAC unit can provide high quality.

Embedded operating system uses Nucleus PLUS, Nucleus PLUS real-time operating system developed by Accelerated Technology Embedded RTOS product, just a one-time purchase of Licenses, to get the operating system source code. The final form is a C library to the user, you can select the desired part of the chain into the application. Has the following features:

1) Fast response time: the detection of critical resources, time does not depend on the possession of the critical resources of the length of the thread execution time, when out of low-priority thread to release critical resources (regardless of whether executed), high-priority thread will seize the run.

2) modules independent of each other: the execution time of each task and other tasks unrelated to the processing time.

3) high throughput: With the increase in the number of tasks, task scheduling time is constant.

4) scalability: the use of a combination of the existing system calls available to the new system calls.

5.2 validation process

Developed in this project we intend to achieve universal device embedded in the interactive interface, in which the application of adaptive thinking.

The first is the hardware design, the design of 8 Ied digital control, 8 buttons Key1 ~ Key8. This part of the design function in two ways:

1) data collection devices to collect data and LED displays the results;

2) users can view and set the key parameters of the device.

Followed by some necessary definitions, the functions of the buttons made by the project group discussed the definition in Table 1.

Defined in Table 1 provide a basis to define the message. Press the function key into an OK message, press the Cancel button will send a CANCEL message, the other key events and so on. We then get a message that an enumerated definition.

Table 1 keys defined


Interface state definition. HCI work into the work, verify and set the state. Each state, said with a MenuSTatus enumeration constant, NORMAL, said working state, CHECKI-NG said that the verification status, SETHNG that set the state. NORMAL state at the time of normal operation, press the function key once to enter the menu will be verified or set the state.

Interactions are defined as follows:

1) normal default for each channel loop real-time data display, an alarm, the alarm can be identified;

2) the default, press the function key to access the normal Level 1 menu, press the turn button, scroll down to display the 1 -, 2 -, 3 -, ... ,14-Reset;

3) status for 2 - and state 4 - can be used as extended;

4) state of 3 -, press the function key to enter the date and time settings menu, press the turn button, scroll down to display the date, time, set up, press the function key OK to exit;

5) state of 4 -, press the function key to enter the parameter setting menu, press the turn button, scroll down to display 4-1,4-2,4-3 ... ... ,4-19, said channel selection; < / P>4-x

state, press the function key to enter the x-channel parameter settings menu, press the turn button, scroll down to display the 4-xO ,4-x-2 ,4-x-3, ... ,4-x -8, press the function key to enter the x-channel y (0 y 8) parameter setting menu, press the plus 1 key, you can shift by a key and modify the operating parameters; modify the parameters are determined by function key to exit; < / P>

6) in any state, according to Key7 return upper;

7) in either state, press the Cancel button to return to normal.

And then follow the interactions defined above, define the menu function which the node. Created in the menu to function pointer to node. The model can also be used to enable interactive communications.

Instance of the HCI, not only to achieve simplicity, the development of high efficiency, but also the structure of open, easy to control the size of the interface.

6 Conclusion

Proven by works, consider the adaptive-based embedded HCI program has the following characteristics:

1) easy to maintain, in the case of topology change, with the key or enter a different data structure easy to be modified. Menu node can change with the needs of members of the actual project, the proxy class can be modified with the actual demand.

2) open, and easy expansion. As long as memory allows, in theory, the scale is not limited menu, and add or delete nodes easy to implement. Menu structure can be statically declared, you can also use dynamic memory allocation.

3) versatility, not only Led digital tube and adapted to the combination of keys, but adapted to the LCD screen and keypad or touch screen. As long as the user interacts with the system, can produce a message-driven areas can be used.

4) high efficiency, from the root to any node in the route does not require software, the decision by the user interaction. Although the network model, but for users, from the function is still a layered structure, context more clearly and easily mastered by the developer.

In addition, specific applications, the realization of adaptive mixed pattern may also occur.

Future research is to examine the host and the target in the case of interaction, how HCI solution to the migration target to achieve the target HCI dynamic configuration.

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