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电梯满载开关不是安全保护装置。()

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The following information should be used when answering question 1.
1 Introduction
The island of Oceania attracts thousands of tourists every year. They come to enjoy the beaches, the climate and to
explore the architecture and history of this ancient island. Oceania is also an important trading nation in the region
and it enjoys close economic links with neighbouring countries. Oceania has four main airports and until 1997 had
two airlines, one based in the west (OceaniaAir) and one based in the east (Transport Oceania) of the island. However,
in 1997 these two airlines merged into one airline – Oceania National Airlines (ONA) with the intention of exploiting
the booming growth in business and leisure travel to and from Oceania.
Market sectors
ONA serves two main sectors. The first sector is a network of routes to the major cities of neighbouring countries.
ONA management refer to this as the regional sector. The average flight time in this sector is one and a half hours
and most flights are timed to allow business people to arrive in time to attend a meeting and then to return to their
homes in the evening. Twenty five major cities are served in the regional sector with, on average, three return flights
per day. There is also significant leisure travel, with many families visiting relatives in the region. The second sector
is what ONA management refer to as the international sector. This is a network of flights to continental capitals. The
average flight time in this sector is four hours. These flights attract both business and leisure travellers. The leisure
travellers are primarily holiday-makers from the continent. Twenty cities are served in this sector with, on average, one
return flight per day to each city.
Image, service and employment
ONA is the airline of choice for most of the citizens of Oceania. A recent survey suggested that 90% of people preferred
to travel ONA for regional flights and 70% preferred to travel with ONA for international flights. 85% of the
respondents were proud of their airline and felt that it projected a positive image of Oceania. The company also has
an excellent safety record, with no fatal accident recorded since the merging of the airlines in 1997. The customer
service of ONA has also been recognised by the airline industry itself. In 2005 it was voted Regional Airline of the
Year by the International Passenger Group (IPG) and one year later the IPG awarded the ONA catering department
the prestigious Golden Bowl as provider of the best airline food in the world. The courtesy and motivation of its
employees (mainly Oceanic residents) is recognised throughout the region. 95% of ONA employees belong to
recognised trade unions. ONA is perceived as an excellent employer. It pays above industry average salaries, offers
excellent benefits (such as free health care) and has a generous non-contributory pension scheme. In 2004 ONA
employed 5400 people, rising to 5600 in 2005 and 5800 in 2006.
Fleet
Fleet details are given in Table 1. Nineteen of the Boeing 737s were originally in the fleet of OceaniaAir. Boeing 737s
are primarily used in the international sector. Twenty-three of the Airbus A320s were originally part of the Transport
Oceania fleet. Airbuses are primarily used in the regional sector. ONA also used three Embraer RJ145 jets in the
regional sector.
Performance
Since 2004 ONA has begun to experience significant competition from ‘no frills’ low-cost budget airlines, particularly
in the international sector. Established continental operators now each offer, on average, three low fares flights to
Oceania every day. ‘No frills’ low-cost budget airlines are also having some impact on the regional sector. A number
of very small airlines (some with only one aircraft) have been established in some regional capitals and a few of these
are offering low-cost flights to Oceania. A recent survey for ONA showed that its average international fare was double
that of its low-cost competitors. Some of the key operational statistics for 2006 are summarised in Table 2.
ONA have made a number of operational changes in the last few years. Their website, for example, now allows
passengers to book over the internet and to either have their tickets posted to them or to pick them up at the airport
prior to travelling. Special promotional fares are also available for customers who book on-line. However, the website
does not currently allow passengers to check-in on-line, a facility provided by some competitors. Furthermore, as
Table 2 shows, a large percentage of sales are still commission sales made through travel agents. Direct sales are
those sales made over the telephone or at the airport itself. Most leisure travellers pay standard or economy fares and
travel in the standard class section of the plane. Although many business travellers also travel in standard class, some
of them choose to travel business class for which they pay a price premium.
In the last three years, the financial performance of ONA has not matched its operational success. The main financial
indicators have been extracted and are presented in Table 3. In a period (2004–2006) when world-wide passenger
air travel revenue increased by 12% (and revenue from air travel to Oceania by 15%) and cargo revenue by 10%,
ONA only recorded a 4·6% increase in passenger revenue.
Future Strategy
The management team at ONA are keen to develop a strategy to address the airline’s financial and operational
weaknesses. One suggestion has been to re-position ONA itself as a ‘no frills’ low-cost budget airline. However, this
has been angrily dismissed by the CEO as likely to lead ‘to an unnecessary and bloody revolution that could cause
the death of the airline itself ’.
Required:
(a) Using the information provided in the scenario, evaluate the strengths and weaknesses of ONA and their
impact on its performance. Please note that opportunities and threats are NOT required in your evaluation.
(20 marks)

【问题 1】（8 分）
用回溯法求解此 0-1 背包问题，请填充下面伪代码中（1）～（4）处空缺。
回溯法是一种系统的搜索方法。在确定解空间后，回溯法从根结点开始，按照深度优先策略遍历解空间树，搜索满足约束条件的解。对每一个当前结点，若扩展该结点已经不满足约束条件，则不再继续扩展。为了进一步提高算法的搜索效率，往往需要设计一个限界函数，判断并剪枝那些即使扩展了也不能得到最优解的结点。现在假设已经设计了BOUND(v,w,k,W )函数，其中 v、w、k 和 W分别表示当前已经获得的价值、当前背包的重量、已经确定是否选择的物品数和背包的总容量。对应于搜索树中的某个结点，该函数值表示确定了部分物品是否选择之后，对剩下的物品在满足约束条件的前提下进行选择可能获得的最大价值，若该价值小于等于当前已经得到的最优解，则该结点无需再扩展。
下面给出 0-1背包问题的回溯算法伪代码。
函数参数说明如下:
W：背包容量；n：物品个数；w：重量数组；v：价值数组；fw：获得最大价值时背包的重量；fp：背包获得的最大价值；X：问题的最优解。
变量说明如下：
cw：当前的背包重量；cp：当前获得的价值；k：当前考虑的物品编号；Y：当前已获得的部分解。

限位开关和极限开关可以用自动复位的开关，但不能用磁开关。()

北京市地方标准DB11/419-2007《电梯安装维修作业安全规范》中规定，施工作业用电应以产权单位指定的电源接电，使用专用的电源配电箱，配电箱应能上锁。()