Rem Construction (Pvt,) Ltd., Singapore is the leading global partners of Highway construction. On June 13th, 1978 Rem Construction (Pvt,) Ltd became the first highway constructing company in Singapore. After couple of month later company started their second and third international office at Nagoya - Japan, and Durham - United Kingdom. At the time company also explored Canadian business market and has open it's third international office in Toronto as well.
The Rem Construction has two supply bases located in Chennai India and Pusan Korea. The Korean yard supply the required machineries such as motor graders, dirt loaders, concrete mixers, tractors, power shovels, belt conveyers, pneumatic rollers, asphalt distributors and other highway construction equipment to the all of Rem construction sites and Indian yard supply the raw materials required on highway construction such as cement, safety equipment, sand, tar, sign board, paint, metal covers, concrete guiders, pipes and polymer mats.
Talking about the Rem, the some of well known board of directors of Rem company are Dr. Gerard Ee is Chairman of the Rem Construction (Pvt,) Ltd., and he is holding B.Eng. degree from International University of Japan and PhD from Durham University of United Kingdom. Dr. Chay Yee Meng vice-chairman, former head of State Audit & Tax Authority of Malaysia, Mr. Steven Chong Managing Director for Rem Construction, he was the founder of Zieon Builders (Pvt.) Ltd. Malaysia, until it closes business with selling it's all shares to State Building Corporation of Maldives. Mrs. Eunice Tay, is serving to the company from the beginning and she is Chief Operations Officer, Director of Marketing, and head of Managing Directors of Rem Construction.
The Rem is multinational company, and it's highly respects on provide equal employment opportunities for all of Rem employees. The equal opportunities policy governs company wide assures that there will be no discrimination against or harassment of any employee or job applicant either directly or indirectly.
Since launch in June 1978, Rem has steadily developed its services world wide, with enhancing it's servicers in the highway construction industry.
Rem stand today in the forefront of the highway construction sector around the world providing durable solutions on highway construction projects including design, procurement and construction for Rem customers both in the state and private sector. Many of these countries, this was the first time that customers are served by fully filed solution on the sector.
The company offers easy payment planes to customers both in the state and private sector. Also, the latest business plane is to extend the construction market in to rail construction. Moving further more, the latest company plane to provide cyber marketing to facilitate globalize customers, and extend sales promotion on international trade fairs as well.
Rem Construction knows global requirement hence the world knows about Rem Construction, especially with its goodwill and friendly relationship. The Rem always fills challenges of future construction requirement.
Rem Constriction (Pvt.) Ltd., overriding mission is to be a backbone of global transportation construction industry and provide co facilities to its' globalised customers at their doorstep, with innovative and sustainable corporate social responsibilities initiatives.
1.1: Organizational Information.
Head Office of Rem Construction located in Singapore and it is consists of several departments. Each department play different role, the following are the descriptions of the individual role/responsibilities of each department.
- Board of Directors / Higher Management level. The Higher Management level developed strategic planes to meet the company mission and future goals. On the other hand this level; of the company is responsible on development company plane as well. Not only that they also hold the responsibilities of day to day running of the company.
- Internal Auditing Department. Internal Auditing Department is responsible on carrying out auditing of all sub department of company in corporate wise.
- Department of Finance. This department deals with all financial activities, including internal affairs as well as marketing/sales.
- Operations and Administration Department.
This level is responsible on maintain key contact with higher management leveling corporate wide. In addition they have to monitor company plane provide feed back to the higher management level. Not only those they are also responsible personal and internal affairs of the company.
- Sales and Marketing Department.
- Construction and Engineering Department.
- Transport Department.
- IT Department.
They handle most of customer focused part of the company, starting with sales promotion to customer help lines, sales and service providing.
This department plays the vital role in company business, and they are responsible on including design, procurement and construction. Also they are responsible for internal engineering works as well.
The department mainly works as a co department of sales and marketing. They are responsible on maintain stocks, handle shipments, and provide the general transport requirement of the company.
Responsible for providing day to day IT servicers, and develops the company data and informational strategy.
The Rem Mobile is on constructional operations in three other countries other than Singapore, they are Japan, United Kingdom and Canada. The Indian and Korean operations are to provide resources to the Rem business. The present organizational structure has penetrated to each country as well. Hence those countries have same company management structure under supervision of Singapore management. The Singapore finance department also responsible for generating accounts and finance facility for corporate business. Hence Finance Departments of each other corporate sites are sub department of Singapore Finance department. Departments of both Korean and Indian yards run under authority of Singapore departments as subdivision of each of them.
2.0 Current WAN Architecture of company.
Simple LAN/WAN Configuration of Company.
Since 1978, in each site, the informant handling is done by bookkeeping. With the business expansion, there was a big bottleneck on information handling. The solution was added in late 1998. The first simple network structure build with Windows 98 OS with Pentium II systems. In early stage WAN connectivity is handled through 56kbps, dial-up connection. With the time each site moved to ADSL internet connection. The existing LAN environment has majority of Microsoft Windows line operating systems including Windows 98, 2000, XP, Vista as well as 7'. Also there are some Apple Macintosh systems as well. Each site has wireless access facilities for mobile users and dumb terminal facilities for purposes' like billing, daily attendance, and fuel card. The existing switches and hubs are 10 to 100 Mbps. Every office has single switch, and several hubs which used to distribute STAR topology based LAN. Other than couple of machines, the networked machines are used shared basis and logging in to database located at Singapore head office. The network multi mode machines are used for all companywide printing, scanning and coping purpose. Singapore site contain centralized databases for all other sites world wide. The data base is running in Windows 2000 server environment. For worldwide employers as well as customers are provided web accesses through web server running in those Singapore based Windows Servers.
LAN structure of Singapore Head Office.
LAN structure of Japan, Canada, and United Kingdom Branch Office
LAN structure of Korean and Indian Branch Office.
These corporate offices are mainly to fill the material and equipment requirement of worldwide work sites. Hence each site has limited staff and limited system requirement as well.
2.1 Usage of Current Network for Business.
The company data/ information/ records are highly important on day to day business as well as long-term business, no doubt that the whole Rem business structure is base on information availability. Present data handling strategy has centralize database implementation interconnected via LAN and WAN. Talking about company information strategy it is important point out that it is not only depend on hardware, software, LAN, WAN, users, and some physical conditions, it also highly depend on data handling & managing method as well as method of storing and detailing.
Rem Construction corporate wide use centralized database structure. The centralized database located in Singapore Head Office. The company maintains data structure which is common to every office. Users of each site access to Singapore data base for data eatery purpose. Also users generate number of informational out puts by logging in to Singapore data bases.
Corporate wide the data base is simply defined as a collection of small peace of single natured information, which is shared over the establishment, more simply it is a reservoir of relational data which is available on demand.
Rem current informational handling structure is based on centralized data base. The main data base is located in Singapore Head office. The database includes web pages for all six sites as well. The database has tables for each site. Those tables includes, data belongs each administrative Department as well as corporate wide signal data tables. Present LAN/WAN facilitate users to access Singapore based centralized database from corporate wide. There are number of tables which are common to all of the sites. The different users in each sites, has different rights to access the tabled records, belongs to the site that user belongs to, as well as other sites.
2.2 Areas where company lacks security and recommendations.
The company present information handling structure is build in late 1998 and so far it has up graded to fill general requirements upgrading are mainly fill information access needs of new employers.
Present centralized database management system was introduced to company in early 2000.
Taking in to account present system, that centralized database system that keeps the data in one single database at one single location. In company environment a single machine called a database server hosts the DBMS and the database. The system facilitated multiple employers or client workstations can work same time on a centralized database system using the Client/Server configuration, or the Intranet configuration if and local area network of each site as well as wide area network is up and running. Attached to the centralized database structure, the client/server architecture is a very successful and popular one. It balances the processing load between the client machine and the data base server. The sudden expansion of Internet and intranet applications has refocused attention on centralized databases. In a situation, the bulk of the processing does not lie on the client machine. It depends on the machine hosting the Application Server and the database server machine. Taking in to account the disadvantage of centralized database systems is that of single point of failure. In case of database fails, work of all employers is interrupted. Also in the case where WANs are used, failure of part of the network means the interruption of work at the remote office. Even though, centralized databases are easier to manage, maintain and control for security purposes. At the end of the day selection of choice if there is no need for a more complex architecture.
Even though the database is reside in server, there the user right assignment is well below the required limit. None of the users assigned minimal user rights to control access. This is one of the points that unauthorized access destruction or manipulation. On top of this point the solution must focus to prevent unauthorized access on any information at companywide. Also provided right must stopped misusing or damaging company data as well.
The communication for accessing recourses located in data base server in head office, as per the present configuration, there is no security set at all. The employers use FTP for data transfer between their work station and server. There should be solution must integrated with new proposal to overcome this. Some security measure like securing WAN and LAN communication with encryption would prevent to the intruder from reading or manipulating the data. On top of this point, because it's open to access, global customers as well as company field employers from remote location, the each LAN environment in all six officers must protected with firewall as well as real time security suite.
The users update and quarrying data from remote site, and number of users access at same time. So the data integrity is quite important. Without any control for anonymous access, the data corruption is highly predictable. Therefore the database access and other rights must be re considerable. One of the popular incidents in office environment is that users theft data, as well as coping data using thumb drives, this have bigger chance of infecting company information environment. Hence rather than limiting access control and user rights, the solution must include some advanced configuration with. Group policies to more detail the security integrity.
The data access with offline cache, makes much security venerability, hence the company wide, off line data access should stop. On the other hand off line data editing trends to violate data integrity as well.
With resent experience the Rem database attacked by several times with Denial of Service, Source code, disclosure of jsp and other point of attacks. One of the highlighted point is, the database management system (DBMS) do not function well. There is number of buffer of low incidents has reported.
Taking overall system in to consideration company information handling is not in good standard. This key factor must be solve as soon as possible.
Other than security the corporate wide LAN structure as well as WAN connectivity is considerably in very poor standard. To meet the company goals, as well as data handling requirement the systems must upgraded and net work peripherals must replaced with newly specified gigabyte connection. The present WAN connections are slower to perform company activities, hence rather than internet connection, the company must facilitate with total communication solution.
3.0 Proposed Distributed Database Design.
3.1 Difference of Proposed Network and Reasons for the proposed network.
Today Rem Construction is leading business place in highway construction, hence the universal data information access is major requirement. As it now Rems' all information is databases concentrated at one mainframe computer site at Singapore head office with worldwide access to this site provided by telecommunications networks, especially over the Internet. Even though the maintaining centralized system and its databases can have grate controlled over information. For example, if the single site goes down, then all users blocked from accessing the databases until the site comes back up again. On the other hand, when it's providing communication facilities, with the far end data base system, the communication cost is much greater. The proposed solution is alternative design to the centralized database concept, which is known as distributed database. The idea is that instead of having one, centralized database, we are going to spread the data out among the worldwide sites on the distributed network. The definition itself, distributed database is a collection of multiple, logical, interrelated database distributed over a computer network. As very simple when a person or process anywhere on the distributed network queries the database at Singapore head office, it is not necessary to know where on the network the data being sought is located. The user just issues the query, and the result is returned. In a distributed database environment this feature is known as location transparency. Because of thescalable implementation of transparency, this can become rather complex indeed. So it must be managed using highly capable software, which is known as a distributed database management systemor in short distributed DBMS (DDBS). It is expressed under definition as a distributed database management system is the software system that permits the management of the DDBS and makes the distribution transparent to the user.
Implementation of distributing data in Reem company network, within major sites located Singapore, Canada, Japan, United Kingdom, Korea, and India. Considering real situation, let's say that the company has a very important technical relational database, which is usedrealtime at all six sites. Imagine that database consists of five large
tables, named AA, BB, CC, DD, and EE, and response time regarding queries made to
the database is an important factor. As it now, the database is centralized, so the arrangement, with all five tables located in Singapore. As the first and simplest solution in distributing the data would be to disperse the five tables among the six sites. In a scenario, that particular tables are used at some sites more frequently than at other sites, it would make sense to locate the tables at the sites at which they are most frequently used. By this approach, if data is commonly used by Japan employers, and table now located in Japan site, users do not need to use any communication facilities, as opposed to when the table only located in Singapore, so in this the Japan employees can exercise local autonomyover the data, taking responsibility for its security, backup and recovery, and concurrency control. Taking in to account the current centralized approach, one of the major issues is about information availability. In a real situation the centralized approach, if the Singapore site link went down, no other site on the network could access Table EE or the rest. If we consider dispersed approach with this, in the dispersed approach of (imagine that Table AA & Table BB located in Singapore site, Table CC located in Japan site, Table DD located in Canadian site, and Table EE located in Korean site) if the Japan site goes down, Table CC is not available to the other sites. On the other hand when the database was centralized at Singapore, if a query issued at any of the sites that required a examine two or more of the tables could be handled in the standard way by the computer at Singapore. The result of the query then is sent to the site that issued the query. Comparatively dispersed approach, query should make together with two sites this is much complex. Talking about new solution, it is distributed database with heterogeneous approach. The tables are distributed through all six sites. Here the idea to allow database tables to be duplicated. The term used with distributed database is replicated at two or more sites on the network. The new approach has number of advantageous. In first case, when a table is replicated at two or more sites and one of those sites goes down, all users at each site on the network can still access the table at the other site(s). Also, in case if more than one site requires frequent access to a particular table, the table can be replicated at each of those sites. On the other hand by this, it minimizes the communication cost during data access as well. Another advantage of this approach is, in a situation, when two table needs to query together, because copies of a tables can be located at single sites, the approach allowing the joins to take place at those sites without having the complexity of having to join tables across multiple sites. The new proposal, to copy the entire database at headquarters in Singapore and to have each table replicated exactly once at one of the other sites. So, this improves availability, at least to the extent that each table is now at two sites. On the other hand, because each table is at only selected sites, the security and concurrency exposures are limited. Also any combination of tables that has to be executed can be handled at Singapore site as well as two other. It is flexible, the administrator can located replication so as to make higher performance.
- Some of point considered on placing replication/tables,
- Place the replicates of tables at the sites that use those most heavily in order to minimize communications costs.
- Ensure that there are at least two copies of important or frequently used tables to realize the gains in availability.
- Limit the number of copies of any one table to control the security and concurrency issues.
- Avoid any one site becoming a bottleneck.
4.0 Concurrency Control in Distributed Database.
In situation that replicated tables to be dispersed all over the sites, the problems of concurrent update expand, too. One of the common possibilities that the “lost update” is still there. In a situation that two people attempt to update a particular record of Table BB in Japan at the same time, still the problem of concurrent update is exists. Adding the problem with distributed database system if one employer updates a particular value in a record of Table BB in UK site at the same time that another employer updates the very same value in the very same record of Table BB in Canadian site, the final result is going to be wrong. Or if there was a very simple timing gap between two alteration, the last updaters result get registered, regardless the value is latest or not. Hence the database management system/application designs to overcome this problem. the solution to meet, the nature of the data and of the applications that use it to tolerate retrieved data not necessarily being up-to-the-minute accurate, then several “asynchronous” approaches to updating replicated data can be used. As a example, the site at which the data was updated, Singapore in the above example involving Table BB, can simply send a message to the other sites that contain a copy of the same table, in this case UK which also has a copy of Table BB, in the hopes that the update will reach UK reasonably quickly and that the computer in UK will update that record in Table BB right away. The other option is there to occupy in this problem is, asynchronous scheme, that one of the sites can be elected to gather all of the updates to all of the tables. That elected site responsible on transmit the changes to all of the other sites on a regularly timing basis. Or each table can have elected site be declared the “dominant” site for that table. All of the alteration for particular table can be sent to the copy of the table at its dominant site, which can then transmit the updates to the other copies of the table on some timed or other basis. But if the natures of the data and of the applications that use it require that all of the data in the replicated tables located in all sites always be consistent, accurate, and up-to-date, then a more complex synchronous procedure must be put into place. Although there are variations on this theme, the basic process for accomplishing this is known as the two-phase commit.
Each computer on the network has a special log file in addition to its database tables. So, each of the six cities has one of these special log files. So the update is to be made at one site, the distributed DBMS has to do several things. In first point it has to freeze all of the replicated copies of the table involved, send the update out to all the sites with the table copies, and then be sure that all the copies were updated. After all of that happens, all of the replicated copies of the table will have been updated and processing can resume. To remain integrity of this, either all of the replicated files have to be updated or none of them must be updated. One of the special cases, if selected alteration of a Table don't want update to take place at some of the sites and not at the others, which would obviously leave inconsistent results. As a example Table DD. Copies of Table DD are located in Singapore, Canada, and Japan. So one of employer an update request to a record in Table DD in Japan. In the first or “prepare” phase of the two-phase commit, the computer in Japan sends the updated data to Singapore and Canada. The databases in all three countries write the update to their logs (but not to their actual copies of Table DD, at this point). The computers in Singapore and UK attempt to lock their copies of Table DD to get ready for the update. If another process is using their copy of Table DD, then they will not be able to do this. Singapore and Canada then report back to Japan whether or not they are in good operating shape and whether or not they were able to lock Table DD. The computer in Japan takes in all of this information and then makes a decision of whether to go ahead with the update or to abort it. If Singapore and Canada report back that they are up and running and were able to lock Table DD, then the computer in Japan will decide to go ahead with the update. If the news from Singapore and Canada was bad, Japan will decide not to go ahead with the update. So, in the second or “commit” phase of the two-phase commit, Japan sends its decision to Singapore and Canada. If it decides to complete the update, then all three cities transfer the updated data from their logs to their copy of Table DD. If Japan decides to abort the update then none of the sites transfers the updated data from their logs to their copy of Table DD. All three copies of Table DD remain as they were, and Japan can start the process all over again. The two-phase commit is certainly a complex, costly, and time-consuming process. It should be clear that the more volatile the data in the database is, the less attractive is this type of synchronous procedure for updating replicated tables in the distributed database.
5.0 Data location and distributed design.
In a distributed database in which no single computer (no single site) in the network contains the entire database, there is the possibility that a query will be run from one of the computers that requires a join of two or more tables that are not all at the same computer. Consider the distributed database design, that a query issued at Singapore requires the join of Tables EE and DD. First point, neither of the two tables is located at Singapore, the site that issued the query. Then, notice that none of the other four cities contains a copy of both Tables EE and DD. That means that there is no one city to which the query can be sent for complete processing, including the join. In order to handle this type of distributed join situation, the distributed DBMS must have a sophisticated capability to move data from one city to another to accomplish the join. Similarly, the distributed DBMS must have its own built-in expert system that is capable of figuring out an efficient way to handle a request for a distributed join. This distributed DBMS expert system will work hand-in-hand with the relational query optimizer, which will still be needed to determine which records of a particular table are needed to satisfy the join, among other things. In the example of the query issued from Singapore that requires a join of Tables EE and FF, there are several options,
- Involved in the join and send copies of them from either Japan or Canada (each of which has a copy of Table EE) to either Korea or India (each of which has a copy of the other table involved in the join, Table DD). Then, execute the join in whichever of New Korea or India was chosen to receive the records from Table EE and send the result back to Singapore.
- Figure out which records of Table F are involved in the join and send copies of them from either Korea or India (each of which has a copy of Table DD) to either Japan or Canada (each of which has a copy of the other table involved in the join, Table EE). Then, execute the join in whichever of Japan or Canada was chosen to receive the records from Table FF and send the result back to Singapore.
- Figure out which records of Table EE are involved in the join and send copies of them from either Japan or Canada (each of which has a copy of Table EE) to Singapore, the city that initiated the join request. Figure out which records of Table DD are involved in the join and send copies of them from either New Korea or India (each of which has a copy of Table DD) to Singapore. Then, execute the join in Singapore, the site that issued the query.
- The options of the distributed DBMS decide must consider:
- The number and size of the records from each table involved in the join.
- The distances and costs of transmitting the records from one city to another to execute the join.
- The distance and cost of shipping the result of the join back to the city that issued the query in the first place.
As example, if only 20 records of Table EE are involved in the join while all of Table DD is needed, then it would make sense to send copies of the 20 Table EE records to a city that has a copy of Table DD. The join can then be executed at the Table DD and the result sent back to Singapore. One solution would be to send the 20 records from Table EE in Japan to Singapore, one of the cities with Table DD. The query could then be executed in Singapore and the result sent to Canada, which issued the query. The reason for Japan and Singapore rather than UK and Korea, the other cities that have copies of Tables EE and DD, respectively, because the distance (and probably the cost) between Japan and UK is much less than the distances involving Canada and Korea. Finally, about the option of shipping the data needed from both tables to Singapore, the city that issued the query, for execution, the entirety of Table DD is needed for the join in this example. Shipping all of Table DD to SIngapore to execute the join there would probably be much more expensive than the Canada option.
6.0 Distributed Directory Management.
Assuming that when a query is issued at any site on the network, the system simply “knows” where to find the data it needs to satisfy the query. But that knowledge has to come from somewhere, and that place is in the form of a directory. A distributed DBMS must include a directory that keeps track of where the database tables, the replicated copies of database tables (if any), and the table partitions (if any) are located. Then, when a query is presented at any city on the network, the distributed DBMS can automatically use the directory to find out where the required data is located and maintain location transparency. That is, the person or process that initiated the query does not have to know where the data is, whether or not it is replicated, or whether or not it is partitioned. Which brings up an interesting question. Where should the directory itself be stored? As with the matter of how to distribute the database tables themselves, there are a number of possibilities, some relatively simple and others more complex, with many of the same kinds of advantages and disadvantages. The entire directory could be stored at only one site, copies of the directory could be stored at several of the sites, or a copy of the directory could be stored at every site. Actually, since the directory must be referenced for every query issued at every site and since the directory data will only change when new database tables are added to the database, database tables are moved, or new replicated copies or partitions are set up (all of which would be fairly rare occurrences),