Tài liệu miễn phí Tổ chức sự kiện
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This paper presents SIENA, an event notification service that we have de-
signed and implemented to maximize both expressiveness and scalability. In
Section 3we describe the service’s formally defined application programming in-
terface,which is an extension of the familiar publish/subscribe protocol [Birman
1993]. Several candidate server topologies and protocols are presented in Sec-
tion 4.We then describe in Section 5 the routing algorithms used by the service
to deliver event notifications to clients; these algorithms are designed specifi-
cally for distributed networks of event servers. This is followed by a description
of strategies for optimizing the performance of the notification selection process.
Supported in part by the results of...
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In its most general form, a distributed event notification service is composed
of interconnected servers, each one serving some subset of the clients of the
service, as shown in Figure 1. (Some use the terms proxy and broker instead
of the term server.) The clients are of two kinds: objects of interest, which are
the generators of events, and interested parties, which are the consumers of
event notifications. Of course, a client can act as both an object of interest
and an interested party. Both kinds of clients interact with a locally accessible
server, which functions as an access point to the networkwide service. In prac-
tice, the...
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In terms of interconnection topology, there are essentially two broad classes
from which to choose: a hierarchy and a general graph. Existing distributed
event notification services, such as JEDI [Cugola et al. 1998] and TIBCO’s
product TIB/Rendezvous™, adopt a hierarchical topology. However, our analy-
sis (presented in Section 6) shows that such a topology can exhibit significant
performance problems. In SIENA we have adopted the general graph, which in
common terms means that the servers are organized in a peer-to-peer rela-
tionship, as we detail in Section 4. A hybrid of the two structures—whether
a hierarchy of peers, or peers of hierarchies—is also a topology to consider,
but requires...
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Our desire for the event notification service to be general purpose also compli-
cates the routing problem for the service. In particular, we assume that objects
of interest have no knowledge of interested parties. Therefore, event notifica-
tions cannot be addressed and routed in the same, relatively simple manner
as, for example, an electronic mail message. Moreover, we cannot assume any
particular locality of objects of interest and interested parties, which is a fact
that bears a strong relationship to the server topology issue. At best we can
only try to take advantage of any locality or structure in the message traffic as
it emerges.We demonstrate below that...
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Given these considerations, solving the routing problem can be seen as a
choice among three alternatives. Common to the three alternatives is the need
to broadcast some piece of information to all the servers in the network, where
the broadcast is required by the lack of a priori knowledge of locality. The first
alternative broadcasts notifications, which implies that notification matching
is performed at each local server based on the subscriptions received at that
server. This alternative suffers from the drawback that all notifications are
delivered to all local servers, whether or not they are serving any parties inter-
ested in the notifications.
The second and third alternatives try...
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Based on our observation about the likely relationship among subscriptions,
the strategy works as follows. When a subscription reaches a server (either
from a client or from another server), the server propagates that subscription
only if it defines new selectable notifications that are not in the set of selectable
notifications defined by any previously propagated subscription. Three bene-
fits accrue from this approach. First, we reduce network costs by pruning the
propagation of new subscriptions. Second, we reduce the storage requirements
for servers. Third, by reducing the number of subscriptions held at each server,
we reduce the computational resources needed to match notifications at that
server. We use a...
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Asmentioned in the introduction, the information associatedwith an event is
represented by a data structure called a notification.We refer to the datamodel
or encoding schema of notifications as the event notification model or simply
event model. Most existing event notification services adopt a simple record-
like structure for notifications, while some more recent frameworks define an
object-oriented model (e.g., the Java™ Distributed Event Specification [Sun
Microsystems 1998] and the CORBA Notification Service [Object Management
Group 1998b]).
Closely related to the eventmodel is the subscription language,which defines
the form of the expressions associated with subscriptions. Two aspects of the
subscription language are crucial to the issue of expressiveness....
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At aminimum, an event notification service exports two functions that together
define what is usually referred to as the publish/subscribe protocol. Interested
parties specify the events in which they are interested by means of the func-
tion subscribe. Objects of interest publish notifications via the function publish.
SIENA extends the publish/subscribe protocol with an additional interface func-
tion called advertise, which an object of interest uses to advertise the notifica-
tions it publishes. SIENA also adds the functions unsubscribe and unadvertise.
Subscriptions can be matched repeatedly until they are canceled by a call to
unsubscribe. Advertisements remain in effect until they are canceled by a call
to unadvertise.
Table I...
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The justification for choosing this typing scheme is scalability. In other sys-
tems, such as one finds for example in the Java Distributed Event Specifica-
tion [SunMicrosystems 1998] andCORBANotification Service [ObjectManage-
ment Group 1998b], a notification is a value of some named, explicit notification
type. This implies a global authority formanaging and verifying the type space,
something which is clearly not feasible at an Internet scale. On the other hand,
we define a restricted set of attribute types from which to construct (arbitrary)
notifications. By having this well-defined set, we can perform efficient routing
based on the content of notifications. As we discuss in Section 7, content-based
routing has...
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While a filter ismatched against a single notification based on the notification’s
attribute values, a pattern is matched against one or more notifications based
on both their attribute values and on the combination they form. At its most
generic, a patternmight correlate events according to any relation. For example,
the programmer of a stockmarket analysis toolmight be interested in receiving
price change notifications for the stock of one company only if the price of a
related stock has changed by a certain amount. Rich languages and logics exist
that allow one to express event patterns [Mansouri-Samani and Sloman 1997].
In SIENA we do not attempt to provide a...
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This expression says that an advertisement covers a notification if and only
if it covers each individual attribute in the notification. Note that this is the
dual of subscriptions, which define the minimal set of attributes that a notifi-
cation must contain. In contrast to subscriptions, when a filter is used as an
advertisement, multiple constraints for the same attribute are interpreted as
a disjunction rather than as a conjunction; only one of the constraints need be
satisfied. Table III shows some examples of the relation ÁN
A . The second exam-
ple is not a match because the attribute date of the notification is not defined
in the...
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The hierarchical architecture is a straightforward extension of a centralized
architecture. It only requires that the basic central server be modified to propa-
gate any information that it receives (i.e., subscriptions, etc.) on to its “master”
server. In fact, the server/server protocol we use within the hierarchical archi-
tecture is exactly the same as the protocol described in Section 3 for commu-
nication between the servers and the external clients of the event notification
service. Thus, in terms of communication, a server is not distinguished from
objects of interest or interested parties. In practice, this means that a server
will receive subscriptions, advertisements, and notifications from its “client”
servers,...
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In the acyclic peer-to-peer architecture, servers communicate with each other
symmetrically as peers, adopting a protocol that allows a bidirectional flow of
subscriptions, advertisements, and notifications. Hence we use an undirected
graph to represent the topology of this architecture. (As always, the external
clients of the service use the standard client/server protocol described in Sec-
tion 3.) The configuration of the connections among servers in this architecture
is restricted so that the topology forms an acyclic undirected graph. Figure 6
shows an acyclic peer-to-peer architecture of servers. The communication be-
tween servers is represented by thick undirected lines, while the communica-
tion between clients and servers is represented by...
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Removing the constraint of acyclicity fromthe acyclic peer-to-peer architecture,
we obtain the general peer-to-peer architecture. Like the acyclic peer-to-peer
architecture, this architecture allows bidirectional communication between two
servers, but the topology can form a general undirected graph, possibly having
multiple paths between servers. An example is shown in Figure 7.
The advantage of the general peer-to-peer architecture over the previous
two architectures is that it requires less coordination and offers more flexi-
bility in the configuration of connections among servers. Moreover, allowing
redundant connections makes it more robust with respect to failures of single
servers. The drawback of having redundant connections is that special algo-
rithms must be implemented to...
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For example, in the case of a multinational corporation, it might be reason-
able to assume a high degree of control and coordination in the administration
of the cluster of subnets of the corporation’s intranet. The administrators of
this intranet might very well be able to design and manage the whole network
of event servers deployed on their subnets, and thus it might be a good idea to
adopt a hierarchical architecture within the intranet. Of course, the intranet
would connect to other networks outside of the influence of the administrators.
Thus, what could arise is a general peer-to-peer architecture at the global level,
serving to interconnect different...
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The components of a loosely coupled system are typically designed to operate by generating and
responding to asynchronous events. An event notification service is an application-independent in-
frastructure that supports the construction of event-based systems, whereby generators of events
publish event notifications to the infrastructure and consumers of events subscribe with the infras-
tructure to receive relevant notifications. The two primary services that should be provided to com-
ponents by the infrastructure are notification selection (i.e., determining which notifications match
which subscriptions) and notification delivery (i.e., routing matching notifications from publishers
to subscribers). Numerous event notification services have been developed for local-area networks,
generally based on a centralized...
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The workplace has been recognized internationally as an appropriate
setting for health promotion. The importance of workplace health
promotion was addressed in 1950 and later updated in 1995 in a joint
International Labour Organization/World Health Organization session on
occupational health (5).
Since this time, health promotion in the workplace has been broadly
recommended by international bodies through numerous charters and
declarations, including the 1986 Ottawa Charter for Health Promotion
(6), the 1997 Jakarta Declaration on Leading Health Promotion into the
21st Century (7) and the 2005 Bangkok Charter for Health Promotion in
a Globalized World (8). ...
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The five major NCDs are heart disease, stroke, cancer, chronic
respiratory diseases and diabetes. There is strong scientific evidence
that healthy diet and adequate physical activity (i.e. ≥30 minutes of
moderate intensity physical activity, ≥5 days per week) play an
important role in the prevention of these diseases. Furthermore, it is
estimated that approximately 80% of heart disease, stroke, type 2
diabetes and 40% of cancers can be prevented through inexpensive
and cost-effective interventions that address the primary risk factors. ...
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Addressing diet and physical activity in the workplace has the potential
to improve the health status of workers; contribute to a positive and
caring image of the company; improve staff morale; reduce staff
turnover and absenteeism; enhance productivity; and reduce sick leave,
health plan costs and workers' compensation and disability payments.
This report – the outcome of an event jointly organized by the World
Health Organization (WHO) and the World Economic Forum –
summarizes the current evidence available in addressing the different
dimensions of the workplace as a key setting for interventions designed
to prevent NCDs through diet and physical activity....
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The information compiled in this report reflects evidence collected from
WHP policies in high-income countries, primarily within the European
and North American regions. The scarcity of information and case
studies from low- and middle-income countries was highlighted as an
important gap in the current knowledge that needs to be addressed.
Despite the limits of the available evidence, all stakeholders are
encouraged to develop and implement WHP policies and programmes
tackling unhealthy diets and physical inactivity....
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Gaps in current knowledge
To strengthen current knowledge, particularly on effectiveness,
cost/benefit analysis and the impact on health of WHP programmes,
further research is needed. The development of simple and easy-to-use
validated instruments for diet and physical activity evaluation is
encouraged. There needs to be further exploration of how the evidence-
based diet and physical activity interventions are applied in workplaces
that are in different geographic locations, and that vary in terms of
governmental structure, literacy levels and social norms around different
health behaviours. Identifying and publishing case reports and examples
of international WHP programmes can also constitute supportive
information that will help planners better understand how to develop
global programmes. ...
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The essential role of a multistakeholder approach
Addressing, comprehensively, the issues of diet and physical activity
requires the involvement of a range of stakeholders. A multistakeholder
approach to the development and implementation of WHP policies and
programmes is key to the success, effectiveness and sustainability of
the programmes. Different stakeholders that can play a role in WHP
include: international organizations; ministries of health, labour and
safety; local and municipal governments; nongovernmental
organizations (NGOs); civil society; employers; employees; trades
unions; company health insurance funds; the agriculture industry; food
producers, catering and food distributors; and the sports industry....
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Key elements of successful programmes
Key elements of successful WHP programmes include: establishing
clear goals and objectives, linking programmes to business objectives;
strong management support; effective communication with, and
involvement of, employees at all levels of development and
implementation of the WHP programme; creating supportive
environments; adapting the programme to social norms and building
social support; considering incentives to foster adherence to the
programmes and improving self-efficacy of the participants. ...
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The workplace as a health promotion setting
Workplace health promotion (WHP) programmes, targeting physical
inactivity and unhealthy dietary habits, are effective in improving health-
related outcomes such as obesity, diabetes and cardiovascular disease
risk factors. Enhancing employee productivity, improving corporate
image and moderating medical care costs are some of the arguments
that might foster senior management to initiate and invest in WHP
programmes.
Unhealthy diets and excessive energy intake, physical inactivity and
tobacco use are major risk factors for noncommunicable diseases
(NCDs). In 2005, an estimated 35 million people died of NCDs such as
heart disease, stroke, cancer and diabetes. Around 80% of these
deaths occur in low- and middle-income countries that...
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Brochure chương trình cần cung cấp những thông tin quan trọng như lịch trình của sự kiện, giới thiệu khách mời tiêu biểu, cảm ơn nhà tài trợ và đơn vị tổ chức. Một tờ brochure chương trình được đánh giá là tốt khi chúng có tác dụng bổ trợ, thay vì chỉ đơn giản là tóm tắt, nội dung của chương trình. Có thể sử dụng brochure để giới thiệu về chuyên môn của diễn giả nhằm tiết kiệm thời gian giới thiệu họ trong chương trình, cảm ơn tất cả những người góp phần vào sự thành công...
8/30/2018 2:31:22 AM +00:00
Tham khảo tài liệu 'thu hút công chúng tham gia sự kiện', kinh doanh - tiếp thị, tổ chức sự kiện phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả
8/30/2018 2:31:22 AM +00:00
Tham khảo tài liệu 'tổ chức sự kiện: một nghề thú vị', kinh doanh - tiếp thị, tổ chức sự kiện phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả
8/30/2018 2:31:22 AM +00:00
Việc chuẩn trước cuộc họp tuy rất ngắn nhưng lại mang lại hiệu quả và tiết kiệm thời gian gấp nhiều lần.Trong khoảng thời gian này, bạn xác định mục đích, thời gian của cuộc họp, những công cụ hỗ trợ (máy chiếu,tài liệu…) và đặc biệt là xem xét Có mục lại đích thành rõ ràng phần và nghiêm tham khắc về dự thời họp. gian
Một trong những nhiệm vụ quan trọng nhất để có thể họp hành hiệu quả chính là xác định mục đích của cuộc họp. Mục đích cuộc họp này phải được viết ra giấy...
8/30/2018 2:27:44 AM +00:00
1. Khái niệm:
Hội thảo là cuộc thảo luận về một số vấn đề nào đó có tính khoa học, lý luận và thực tiễn đang đặt ra. Mục đích của hội thảo là làm sáng tỏ cơ sở lý luận, cơ sở thực tiễn của vấn đề, đề xuất, kiến nghị hoặc dự báo vấn đề một cách có cơ sở khoa học. Nội dung của hội thảo sinh viên là xuất phát từ nhu cầu bức bách của cuộc sống sinh viên, từ đòi hỏi của công tác Hội và phong trào sinh viên, giúp các cấp bộ Hội...
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Câu 1) Hành vi tổ chức có mối quan hệ với các môn học
a) Khoa học chính trị
b) Tâm lý xã hội
c) Nhân chủng học
d) Tất cả đều đúng
Câu 2) Những liên minh hình thành một cách tự nhiên từ môi trường công vịêc trên cơ sở những quan hê thể hiện sự thụ cảm giữa các cá nhân được gọi là
a) Nhóm không chính thức
b) Nhóm nhiệm vụ
c) Nhóm chỉ huy
d) Tất cả đều sai
8/30/2018 2:27:40 AM +00:00