J. Cent. South Univ. (2016) 23: 2906−2916
2908
In condition that, each user sends a request to PRM
for resource
i
R
u
and the processing ratability of cloud
servers is supposed to be 100%, the following two cases
occur:
Case 1: Suppose that PRM allocates equal resource
items
)(
RRR
upp
to each user, which PRM needs
to develop the resource items p
R
and the development
cost denotes p
R
·m·p
p
. Thus, the PRM profit can be
represented as Eq. (1) and the user cost can be
represented as Eq. (2); Then, the idle resource items
denote
m
i
RR
i
up
1
)( and the resource utilization of
IRPs is 0.
Case 2: PRM allocates resource items p
R
(the
uncertain relation between p
R
and
i
R
u to each user). PRM
at least needs the resource items p
R
·m. And the
development cost at least reaches the amount of p
R
.
Suppose that there exist resources items k(k<=m)
satisfying the user needs in the existing RSDP, and then
the PRM profit should be represented as F(c)=k·u
p
·p
R
−
m·p
R
·p
p
(k≤m). The total user cost is k·u
p
·p
R
(k≤m) and
the idle resource items is represented as expressed as
m·p
R
−
k
i
R
i
u
1
and the resource utilization of IRPs is 0.
From above discussion, we find that the existing
RSDP, characterized as a centralized allocation
mechanism, assigns the equal resource for each user;
thus, this mode constrains the variability and scalability
of PRM process resource and results in a higher
development cost as well as a lower utilization of process
resource. On the other side, the user charges vary with
PRM price and users have no right to participate in
pricing. So, it is difficult to rent the appropriate process
resource according to user capabilities and expectations.
In this existing RSDP, PRMs ignore the process resource
usability of IRPs and make RSDP almost be in a lower
efficiency and a higher operating cost.
2.1 Foundation of model construction
We introduce the crowdsourcing cloud service to
agile software process and release resource needs by
crowdsourcing pattern. And then we provide software
resources service for team needs and external needs by
collecting the individual resource provider (IRP) from
outside the project team, which thus greatly reduces the
duties and pressure of project resource manager (PRM).
Meanwhile, we proposed the locality-aware resource
scheduling method for optimizing the resource
scheduling in crowdsourcing cloud service pattern
(CCSP) and improve the resource use efficiency in agile
software process. Finally, we reduce the overall resource
consumption and cost for the team, and promote software
process agility.
In our improved model, the centralized pattern of
resource allocation and scheduling has been broken for
sharing PRM responsibilities. In CCSP, PRMs, only as a
resource agent, provide leasing process resource for
individual applicants instead of providing storage
resources directly, and then allocate and schedule
individual storage resources dynamically according to
user expectations and IRPs constraints.
In KantoroVich-Hitchcock problem of operational
research, we find the similar basis that both models’
optimization can be reduced to multi-objective linear
optimization problems. Then this paper further proposes
the improved approach for allocating and scheduling user
storage resource, which finally maximizes the interests
of all parties in CCSP.
According to the mathematical principles of
Kantoro Vich-Hitchcock problems, the resources
scheduling process in CCSP can be described as follows:
PRM, as a resource agent, needs to distribute one kind of
resource provided by m sources (A
1
, A
2
, …, A
m
) to n
resource of IRPs (B
1
, B
2
, …, B
n
). During the allocation
process, users can provide the highest price uP
i
and
regard the price of IRPs as the cost
j
p
p in allocation
process. The balance sheet and price list of CCSP just
seem as that of Cantor los-marvel cork problems, shown
as in Table 1 and Table 2. Obviously, this problem may
be reduced as how PRMs allocate process resource of all
IRPs to maximize benefits under the premise to satisfy
user expectations.
Suppose that
ij
s
u denotes the number of the j-th
PRM resource items assigned to user i. There are three
types that the PRM allocates the IRPs’ resource to users.
The types are as followings: 1) The user sends a
request directly to the IRP. 2) According to the user′s
request parameters, PRM, as an agent, directly allocates
resource. 3) PRM, as an agent, uses formula (3) to
allocate the resource of IRPs.
Because all the IRPs’ parameter does not meet all
Table 1 Balance sheet of CCSP
Resource B
1
B
2
… B
n
User request
A
1
1
R
u
A
2
2
R
u
…
…
A
m
2
R
u
1
R
p
2
R
p
…
n
R
p
Table 2 Price list of CCSP
Resource A
1
A
2
… A
m
B
1
B
2
… B
n
A
1
1
R
u
2
R
u
m
R
u
1
p
p
2
p
p
n
p
p
A
2
1
p
p
2
p
p
n
p
p
…
…
…
…
A
m
1
p
p
2
p
p
n
p
p