Telecommunication Networks

Index

Communication

Wireless Communication

·         Cellular & Non-Cellular Wireless Communication

Types of Wireless Communication

·         Fixed Wireless

·         Mobile Wireless

·         Portable Wireless           

·         IR Wireless

·         Wireless WAN

·         Wireless LAN

Wireless Devices

Wireless Technology

·         Global System for Mobile Communication (GSM)

·         General Packet Radio Service (GPRS)

·         Enhanced Data GSM Environment (EDGE)

·         Universal Mobile Telecommunications System (UMTS)

·         Blue Tooth Technology from INTEL

Wireless Application Protocol (WAP)

·         Wireless Application Environment (WAE)

·         Wireless Session Layer (WSL)

·         Wireless Transport Layer Security (WTLS)

·         Wireless Transport Layer (WTP)

Radar

·         Types of Radar

Security

Conclusion

  

COMMUNICATION:

A link or transfer of information b/w any two objects is called communication.

Wireless Communication:

Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or all of the communication path. Some monitoring devices, such as intrusion alarms, employ acoustic waves at frequencies above the range of human hearing; these are also sometimes classified as wireless.

The first wireless transmitters went on the air in the early 20th century using radiotelegraphy (Morse code). Later, as modulation made it possible to transmit voices and music via wireless, the medium came to be called "radio." With the advent of television, fax, data communication, and the effective use of a larger portion of the spectrum, the term "wireless" has been resurrected.

CELLULAR AND NON-CELLULAR WIRELESS COMMUNICATION:

Wireless communication systems can be roughly divided into two categories: cellular   and non-cellular systems. In cellular systems the area to be covered is divided in a number of cells. All communication in a cell goes via a single base-station located in that cell. Hand-over     protocols and connections between base-stations enable roaming over cell borders. The consequence of this concept is that both an infrastructure and a complex protocol are required.       Non-cellular systems form another category of wireless communication systems for which no infrastructure is required. In this sense the complete system itself is mobile.

 
 

This thesis deals with systems providing short distance, multi-access, ad-hoc based, point-to-point communication links. Shortly, we focus on ``non-cellular wireless communication systems''. Applications can primarily be found as indoor data communication systems as illustrated. This figure only shows a number of properties of the target communication system.

The main properties are listed below:

·         Non-Cellular: Systems do not require an infrastructure. Our target system is a non-cellular communication system for short distances.

·         Multi-Access: Enables several simultaneous communication links. In the figure two such links are shown.

·         Random-Access: This term is in this context defined as the ability of users to initiate a communication link at any arbitrary moment.

·         Digital Data-Communication Links: Although not completely clear from the picture, the target system is a digital communication system. Applications can be both data-links and (via a speech-coder) speech-links.

TYPES OF WIRELESS COMMUNICATION:

·         Fixed Wireless -- The operation of wireless devices or systems in homes and offices, and in particular, equipment connected to the Internet via specialized modems.

·         Mobile Wireless -- The use of wireless devices or systems aboard motorized, moving     vehicles; examples include the automotive cell phone and PCS (personal communications services).

·         Portable Wireless -- The operation of autonomous, battery-powered wireless devices or systems outside the office, home, or vehicle; examples include handheld cell phones and PCS units.

·         IR Wireless -- The use of devices that convey data via IR (infrared) radiation; employed in certain limited-range communications and control systems.

·         Wide Area Network (WAN) -- Building blocks include microprocessors, flash memory, base band chipsets, software and reference designs.

·         Wireless Local Area Network (WLAN) -- Products provide private, trusted, high-speed connectivity, mobile roaming and building-wide coverage for small, medium and enterprise organizations.

WIRELESS DEVICES:

Common examples of wireless equipment in use today include:

·        Cellular Phones And Pagers -- Provide connectivity for portable and mobile applications, both personal and business.

·        Global Positioning System (GPS) -- Allows drivers of cars and trucks, captains of boats and ships, and pilots of aircraft to ascertain their location anywhere on earth.

·   Cordless Computer Peripherals -- The cordless mouse is a common example; keyboards and printers can also be linked to a computer via wireless.

·         ·        Cordless Telephone Sets -- These are limited-range devices, not to be confused with cell phones.

·        Home-Entertainment System Control Boxes -- The VCR control and the TV channel control are the most common examples; some hi-fi sound systems and FM broadcast receivers also use this technology.

·        Remote Garage-Door Openers -- One of the oldest wireless devices in common use by consumers; usually operates at radio frequencies.

·        Two-Way Radios -- This includes Amateur and Citizens Radio Service, as well as business, marine, and military communications.

·        Baby monitors -- These devices are simplified radio transmitter/receiver units with limited range.

Wireless Technology

Wireless technology is rapidly evolving, and is playing an increasing role in the lives of people throughout the world. In addition, ever-larger numbers of people are relying on the technology directly or indirectly. (It has been suggested that wireless is overused in some situations, creating a social nuisance).

More specialized and exotic examples of wireless communications and control include:

·         Global System for Mobile Communication (GSM) -- A digital mobile telephone system used in Europe and other parts of the world; the de facto wireless telephone standard in Europe.

·          General Packet Radio Service (GPRS) -- A packet-based wireless communication service that provides continuous connection to the Internet for mobile phone and computer users.

·          Enhanced Data GSM Environment (EDGE) -- A faster version of the Global System for Mobile (GSM) wireless service.

·         Universal Mobile Telecommunications System (UMTS) -- A broadband, packet-based system offering a consistent set of services to mobile computer and phone users no matter where they are located in the world.

·         Blue tooth* Wireless Technology -- Allows mobile PCs, cellular phones and other devices to communicate together, offering personal connectivity freedom for home and business mobility.  

Wireless Application Protocol (WAP):

WAP (Wireless Application Protocol) is a specification for a set of communication protocols to standardize the way that wireless devices, such as cellular telephones and radio transceivers, can be used for Internet access, including e-mail, the World Wide Web, newsgroups, and Internet Relay Chat (IRC). While Internet access has been possible in the past, different manufacturers have used different technologies. In the future, devices and service systems that use WAP will be able to interoperate.

The WAP layers are:

·         Wireless Application Environment (WAE)

·         Wireless Session Layer (WSL)

·         Wireless Transport Layer Security (WTLS)

·         Wireless Transport Layer (WTP)

Four companies conceived the WAP: Ericsson, Motorola, Nokia, and Unwired Planet (now Phone.com). The Wireless Markup Language (WML) is used to create pages that can be delivered using WAP.

Security

Security of Wireless Transmissions:

Currently, few wireless communication protocols offer encryption of the transmission. In security models of protocols that do have security encryption (such as WAP), there have been identified transmission security weaknesses in current protocols.

RADAR

Radar, which is an acronym for radio detection and ranging, refers to a portion of the electromagnetic spectrum with wavelengths extending from 1 mm. to 1 m. The term microwave, although sometimes used interchangeably with the term radar, is therefore a misnomer since these waves are about 2.5 million times longer than the shortest visible light waves!

Advantages of utilizing these wavelengths include their ability to penetrate haze, light rain, clouds and other atmospheric particulates. Radar views of Earth may be obtained at any time of day (even at night), under most any condition. The images are often very different from those taken in other wavelengths, and hence reveal supplementary information about terrain surfaces. Since microwaves are much longer than visible light waves, radar images often appear "smoother" than visible spectrum images.

Active & Passive:

Radar sensors may be divided into two groups: passive and active. Passive systems simply record microwave-region wavelengths of energy emitted from the Earth's surface. Microwave radiometers are passive systems. The signal they receive is an amalgam of thermal emissions from the ground and the atmosphere, plus scattered emissions originating in the atmosphere and extra terrestrially. Active systems record the reflected signals of microwaves they transmit. This Internet site will concentrate on active radar systems.

Types Of Active Radar:

There are three types of active radar remote sensors. They include:

·         Doppler radar: Commonly used to detect motion (motor vehicle/traffic applications).

·         Plan Position Indicators (PPI): Used by air traffic controllers and weather forecasters.

·         Side-looking airborne radar (SLAR): Originally developed for military reconnaissance in the early 1950s for all-weather, day/night imaging.

Conclusion

The greatest marvel of science which was bestowed on human kind to connect them with one an other, an invisible wire having only one inlet and more then one outlets which has stretched over the world so all the human races can feel and love each other by interacting, listening, learning and sharing each other's ideas like a big family. On the other side this communication has completely changed the scenarios of modern warfare, a warfare with out wires, with out the delay of receiving and sending messages to friendly forces where every bit of information of battle field reaches the command headquarters within microseconds, where super weapons can search and destroy there targets with pin-point accuracy, where any movement of your enemy is not a surprise for you.

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Safety Stock, Inventory Policies

Safety Stock, Inventory Policies

While most modules in an Advanced Planning System are based on the assumption that all planning data are deterministic, in reality usually random events occur. In order to buffer the production plan against these random events (such as random demands, machine breakdowns, late deliveries), often safety stock is used. The determination of the required level of safety stock in the dynamic planning environment of an Advanced Planning System is a non-trivial problem. For a single inventory location that serves a number of downstream nodes in the supply chain, several stochastic inventory policies can be applied.

The size of the safety directly depends on the type of the inventory policy that is in effect. The underlying conception for a single-stage inventory policy is as follows. An inventory node is supplied from a "source" which fulfills orders for the considered product after a certain replenishment lead time. If the source is a production segment or rather production stage of the same company, then the replenishment lead time is a function of the flow time of a production order and depends on numerous factors, the utilization of the production stage being one of them. If the source is another inventory node of the company, then the order is a demand observed by this inventory node and the replenishment lead time depends on the inventory available on hand as well as on the time required for material handling and transportation processes. If the source is an external supplier, then the replenishment lead time is equal to the customer order waiting time provided by the supplier, plus an additional time required for material handling and transportation. In all mentioned cases it is clear that the replenishment lead time may be subject to random variations.

For the correct calculation of the parameters of an inventory poliy it is crucial to model the time axis of the inventory process as precise as possible. Basically the time axis can be modeled as continous or as discrete. In practice, the time axis of logistical processes is discrete. The MRP (material requirements planning) calculations that are standard in all ERP/MRP/AP systems are based on a discrete times axis. By contrast, as far as inventory policies are supported, most software systems model the time axis as continuous. This may lead to significant planning errors with the result that the service levels are goals are missed.

• Modeling of the Time Axis

Inventory policies differ in two aspects, namely the mechanism used to trigger replenishment orders and the decision rule that specifies the determination of the order size. The specific inventory policies are defined through the combination of the decision variables $s$ (reorder point), $r$ (review interval, order cycle), $q$ (order quantity) and $S$ (order level) as follows:

• $(s, q)$ policy,
• $(r, S)$ policy,
• $(s, S)$ policy.

$(s,q)$ policy

Under the $(s, q)$ policy, the point in time at which replenishment orders are triggered, depends on the size of the reorder point $s$, whereas the order quantity $q$ is constant over time. In the ideal (textbook) form of the $(s, q)$ policy, the inventory position is continuously monitored. The inventory position is the sum of the inventory on hand plus the inventory on order minus the outstanding backorders (backlog). The inventory management system (or the inventory manager) acts according to the following decision rule: If at a review instant the inventory position has reached the reorder point $s$ (from above), then launch a replenishment order of size $q$.

In reality the inventory is not monitored continuously. In contrast, the replenishment decisions are made in discrete time intervals, usually at the end of a day. In addition, often demand sizes are greater than one unit. Under these conditions, the analysis of the $(s, q)$ policy as presented in many textbooks in false, as the so-called undershoot is neglected. In the above figure, the undershoot is the difference between s and the inventory position at the moment immediately before a new replenishment order is released. Neglecting the undershoot usually results in significant over-estimation of the service level (under-estimation of the required safety stock).

(r,S) policy

If an $(r, S)$ inventory policy is in effect, the points in time at which replenishment orders are released are determined through the review interval $r$. The inventory management system proceeds according to the following decision rule: In constant intervals of $r$ periods launch a replenishment order that raises the inventory position to the target order level $S$. Obviously, the $(r, S)$ policy is an inventory policy with periodic review. The order size at a time of a review depends on the demands and the development of the inventory observed in the preceding periods. If $r=1$, then this policy is called base-stock policy.

$(s,S)$ policy

Under an $(s, S)$ inventory policy, the points in time when an order is triggered are determined policy, i. e. through the reorder point $s$. However, the order quantity is now, similar to the $(r, S)$ policy, a function of the inventory development over time. In the literature this policy is sometimes characterized with the help of a third parameter which specifies the length of the review interval $r$. In this notation the policy is called $(r, s, S)$ policy. In the case of $r = 0$, continuous review is in effect. If demands arrive unit-sized, then the $(r= 0, s, S)$ policy is identical to the $(s, q)$ policy with continuous review.

For the determination of the optimum safety stock under conditions of uncertainty the demand during the risk period plays a central role.

The risk period is composed of

• The review period and
• The replenishment leads time.

Stochastic demand occurs within this time span that usually comprises several periods. In order to compute the parameters of an inventory policy, we must know the probability distribution of the demand during the risk period.

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Best Practices in Inventory Management

Best Practices in Inventory Management

A leading consumer products company dealing in cosmetics and other personal care products was seeking ways to:

Ø     Reduce inventory levels across their forward supply chain

Ø  Improve Inventory Record Accuracy at their storage points

Ø  Accurately track damaged goods at various points in the supply chain

The above problems together were a significant burden to the company.

Implementation of best practices after a detailed business analysis resulted in the following benefits:

Ø  Inventory Record Accuracy improved to 95% within 2 months

Ø  Stock levels reduced by about 30% across stocking points in the supply chain

Ø  Complete visibility was achieved in the supply chain with respect to damaged goods inventory. Chains Lightning Fast

Organization Background:

The firm was a leading consumer Products Company dealing in cosmetics and personal care products with its head office located overseas. The company had a supply chain network of 3 factories with bonded stock rooms (BSR) attached for dispatch to the depots and 35 depots for servicing distributors. Goods move from the factory to the SR. BSR dispatches stocks to Mother CFAs (depot). Other depots receive stocks from the Mother depot and sell them to distributors.

Key Concerns for the Company:

1. To reduce inventory level at the BSR and depots.

2. To improve inventory accuracy at stocking points including both BSRs and depots

3. To identify the damaged stocks across the chain and initiate action in a timely manner

Focus of Study

A study was completed focusing on the

1. Inventory-related issues at BSRs and depots. These included:

Ø  Inventory holding as a proportion of sales

Ø  Practices employed for track goods in the warehouse

Ø  Proportion of fast and slow moving stocks to the total inventory

Ø  Linkages of factory dispatches to BSR with patterns of BSR dispatches to depots

Ø  Accuracy of inventory records especially of fast selling lines

2. Demand Planning process. The study looked at:

Ø  Forecast Accuracy and process of reviewing and revising forecasts

Ø  Level of safety stock at each location combined with process to review and reset the same

Ø  Linkages of forecasts and consequent dispatches with relevant available closing stocks at depots

Findings

Key Business Indicators

1. Total average inventory holding at BSRs was 8.2 weeks of sales

2. Average inventory holding at the depots was 6.5 weeks of sales

3. Depots were holding

Ø  High inventory of old/withdrawn stocks

Ø  Damaged stocks for a long time (over 3 months)

4. Book and physical stocks had discrepancy of over 30%

Conclusions

1. High Inventory Levels: Inventory levels were very high across the distribution chain on account of:

Ø  Sales and dispatch forecasts that were not in line with actual primary / secondary sales

Ø  There was no process to periodically review and refine the Annual Forecasts, in line with market feedback

Ø  Stocking across all points in the distribution chain was driven by a push-oriented system that did not have provisions to be tuned to market requirements

Ø  Actual safety stocks maintained at depots were significantly higher that target safety stocks agreed at the beginning of the year. No system was in place to monitor and correct the same during the year

Ø  Stock allocation from depots was manual. Orders received from distributors were manually processes and no process was in place to automatically collate orders and allocate stocks

2. High Levels of Old / Withdrawn / Damaged / Slow-moving stocks: Dead stocks were allowed to accumulate in the system mainly because:

Ø  There was an absence of visibility into inventory details across stocking points

Ø  The process to monitor and act on dead stocks was not adhered to

Ø  Records of slow-moving / old / withdrawn / damaged stocks were not maintained methodically at the stocking points. Records were inaccurate.

Ø  Communication of details of dead stocks to the relevant teams was based on manually filed reports which was time-taking and open to error

3. Inaccuracy in inventory records:

Ø  The organization did not have a clear policy on periodic reconciliation of physical  stock with book records

Ø  Inaccuracies grew over time, compounded with process failure on accounting for dead stocks

Action Steps Advised and Undertaken

Process Improvements

1. Bin card system was implemented for each rack at the CFAs and the delivery staff was trained in relevant bind card maintenance practices.

2. A process to regularly reconcile physical and book stocks using the cycle-count process was mandated

3. And IT solution was identified and implemented for

Ø  Accounting the Cycle count process, providing MIS on deviations and accounting the adjustment notes

Ø  Computing the forecast using consolidated orders, with factoring for promotions and seasonality

Ø  Calculating safety stock level based on number of weeks of sales target

Ø  Facilitating communication of closing stock data from BSR and depots to logistics department

Ø  Facilitating communication of damaged and un-saleable stock quantity to commercial department

Ø  Automatically allocating stocks using FIFO principle at the depots

4. Demand planning and forecasting were made a periodic activity using the above IT solution to align forecasting with market orders and actual sales. The process of setting safety stocks at depots was made periodic and dynamic, based on updated sales data.

5. Norms were set to act on damaged / old and other dead stocks. Clear action steps were laid down to liquidate or destroy these stocks. Responsibility and accountability were set to in the organization to monitor and authorize activities in this regard based on visibility provided by the IT solution.

Benefits:

1. The organization achieved an inventory record accuracy (book stocks correctly reflecting physical stocks) of 95% within 2 months.

2. The company achieved (Within 2 Planning cycles i.e. 2 Months)

a. Stock level reduction

Ø  From 8.2 weeks to 5.5 weeks at the BSR

Ø  From 6.5 weeks to 4 weeks at the depots which included Damaged Inventory

Ø  Reduction in stock Value holding across the supply chain

b. Transparency of saleable and damaged stocks quantities across the supply chain resulting in more accurate demand planning, stock allocation and production.

c. Better management of damaged and un-saleable stocks:

Ø  Sales realization on salvaging and selling damaged stocks at a discounted price

Ø  Timely destruction of unusable and potentially harmful products

Ø  Timely action on transport, handling, stock management and product development fronts to reduce damages.

d. Reduction in proportion of old and damaged stocks; Facilitation of ensuring fresher stocks in the market. This was achieved mainly by reducing inventory levels across the chain and also by better stock management at the depots.

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New Karachi Sewerage Development Plan

Project Objectives a) The meet the targets set out for achieving Millennium Development Goals (MDGs) set by Government of Pakistan. b) To streamline New Karachi area with the provincial development goals set by the Sindh Government. c) To upgrade the downtown areas of the city. d) To divide the drainage load for better flow and lesser hassles specially, during heavy rains. e) To built better and improved drainage using latest technology. f) To gift the inhabitants of New Karachi a healthy living environment. g) To better utilize tax payers’ money in community development.

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Carrom Challenge

Carrom Challenge

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Arif Habib Investments Limited

Insurance Coverage by American Life Insurance Company (Pakistan) Limited

For Participants of  Pakistan Pension Fund

 

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