Bridge Alarm Management System Computer Science Essay

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Its intention is to provide visual and audible indication of alarms. All equipment on the bridge making an audible alarm shall be connected to the bridge alarm system. When an equipment alarm is activated, the Brigde Panel show the alarm in a list on the display, providing information about what the cause is, and in which system the alarm is activated.

The alarm is generated in 30 seconds (first stage)

If not the alarm is ack nowledged in the first stage, the alarm will be transmitted to the selected cabin panels (second stage).

If the alarm is not acknowledged within the pre.set time, the system transmits the alarm to all cabin panels (third stage).

In addition, it provides the function of Bridge Navigational Watch System (BNWAS), which is a watch alarm system that requests bridge watchkeeping crew to periodically push a button. If not, an alarm is triggered in the cabins of deck officers and the captain. BNWA is aimed to detect inability of the watchkeeping crew on the bridge of a vessel.

Text panels are cost effective, but how to ensure they support operator performance?

"A modern bridge is already owerflowing with alarms and buzzers; all demanding the watchkeepers attention, distracting him from his main task."

- How to ensure that the display support operator efficiency rather than reduce it?


Concerning the work environment on a bridge, there is several factors that must be taken into account when developing a product.


Human Error



Interaction design:

- clarity of controls, alarms, displays, status indication.

It is neccesary to be more specific about the usability criteria for the interaction with the HMI.

- Alarm floods

- distraction - information is not a scarce resource, attention is.

- noise level

- fatigue

- stress

- errors

- human factors:

- Vision

- Hearing

Human Factor - Person



Previous training





Religion, national tradition, dress,



Work environment

Temperature, humidity, air quality, lighting,

noise, vibration, cleanliness

Working hours

Continuous operations, watchkeeping


Adequate tools & equipment

Manning levels

Organization structure

Authority, responsibility, communication

Actions by others




Job description



Continuation Training


Education & training


Personal health & hygiene, fitness,

balanced diet


Strength, stamina, stress, fatigue,

pain/discomfort, hunger, thirst,

temperature extremes, vibration,

movement constriction, lack of physical

exercise, disruption of circadian rhythm


Task speed, task load, threat of

failure/loss of job, monotonous, degrading

or meaningless work, long uneventful

vigilance periods, conflicts of motives

about job performance, reinforcement

absent or negative, sensory deprivation,

distractions (noise, glare, movement,

flicker, colour), inconsistent cues


Perception, motor requirements (speed,

strength precision), control-display

relationships, anticipatory requirements,

interpretation, decision-making,

information load, narrowness of task,

frequency & repetitiveness, task criticality,

long/short-term memory; calculation

requirements, feedback (knowledge of

results), dynamic v step-by-step results,

team structure & communication, manmachine


Human Factors - equipment and workspace design


System Design


Human-system interface

Human-human, human machine, humancomputer


Body Size

Body strength & stamina

Limits of strength and endurance

Workplace design

User capabilities and limitations

Stresses and Hazards

Wind, whole body motion, motion induced

fatigue, vibration, noise, darkness/dazzle,

temperature, sleep loss

Vision and Lighting

Human vision, visual displays and lighting


Auditory Information

Transfer of information to human operators

using their hearing

Voice Communication

Characteristics of speech and hearing

Face-to-face and electronically assisted speech



Optimum size, shape, operating dynamics and




Tools & equipment

Handbooks, Procedures

- rules and regulations

- interaction design - user friendliness

Things to have in mind when user testing:

Human errors can be brought on by such characteristics of the working environment such as noise, vibration, lighting, equipment layout and high workloads. Well designed operator focused workplaces and instrument displays, and a strong and accurate operational and maintenance planning and procedure regime, together with a robust safety awareness are all critical in reducing human error.

Deliberate deviations form rules, regulations, procedures and instrutions, violations can arise due to, amongst others:

- the desire to cut corners to save time

- a perception that rules are too restrictive

- Lack of enforcement of the rules such that routine violations becomes the norm, which particulary may effect newly joining engineers.

In order to minimise such violations, it is important to ensure that the mental attitudes and motivations of engineers are considered carefully in all aspects of


- Alarm Design

- Different design concepts for presenting alarm information.

A study conducted by ASM Consortium showed that performance under alarm flood conditions can be improved by presenting the alarms

if the operator interface enables the operator to strategically view subsets of the alarms acssociated with specific equipment areas rather than a list containing all of the alarms.

Poor level of manning induces fatigue, which is root for maritime accidents. Technology might not adress the real problems in shipping industry, like undermanning, proper hours of rest, etc, but by being aware of potential human errors, one may prepare and

Its scope is to collectively manage and present alarm information on the display unit. Alarm information should be sorted and displayed according to the set priority.

Important aspects

By monitoring bridge activity means that user interaction and physical movement

The system is interfaced to all systems on the bridge making audible alarms, and a text display shows what system caused the alarm. The audible alarms can be reset either in ULSTEIN Bridge Alarm System or in the equipment that generated the alarm. The system also has a monitoring function, a "dead-man's alarm", which generates alarm to other personnel if no activity is registered in a certain space of time. In addition, assistance can be called for via a "Call back-up" function that alarms other navigators. ULSTEIN Bridge Alarm System can also be equipped with a voice alarm module, which vocally alerts the nature of the alarm.

The system is designed to enable a near fail-safe, one-man bridge operation through a ladder of alarms or alerts to other qualified navigators, and the master, if a situation that needs attention of others should occur.

To silence the alarm both on the ulstein bas and the equipment generating the alarm:

1:Touch anywhere on the display to turn any audible alarm off (this turns off the audible alarm on the ulstein BAS and on the equipment generating the alarm

- If the alarm state has changed back to normal before the silence button is pushedm the alarm group button will turn to normal state (grey) when silence is activated.


The BAM should distinguish between different alarm states:

.1 unacknowledged alarm; and

.2 acknowledged alarm.

7.3.2 When an alarm condition is detected, it should be indicated as unacknowledged alarm:

.1 initiate an audible signal, accompanied by the visual alarm announcement;

.2 provide a message of sufficient detail to enable the bridge team to identify and

address the alarm condition; and

.3 may be accompanied by speech output presented at least in English, using

harmonized alert voice messages according to the regulations of the Organization.

7.3.3 An unacknowledged alarm should be clearly distinguishable from those existing and already acknowledged. Unacknowledged alarms should be indicated flashing and by an audible signal.

7.3.4 The characteristics of the audible alarm signal, whether used singly or in combination with speech, should be such that there is no possibility of mistaking it for the audible signal used for a warning.

7.3.5 Means may be provided at an HMI to temporarily silence audible alarm signals, if the alert identification is provided at the HMI. If an alarm, which can be acknowledged on the bridge (categories A and B), is not acknowledged within 30 s the audible signal should start again or as specified in the equipment performance standards.

7.3.6 It should be possible to temporarily silence category C alarms. The alarm should be

retriggered after a specified period of time consistent with the Code on alerts and indicators when the alarm is not acknowledged at the specified workplace (e.g., engine-room).

7.3.7 The visual indication for an unacknowledged alarm should continue until the alarm is

acknowledged, unless specified otherwise in the equipment performance standards, e.g., for

CPA/TCPA alerts where the visual signal can be ceased when the alarm condition is rectified.

7.3.8 The audible indication, if not temporarily silenced, for an unacknowledged alarm should

continue until the alarm is acknowledged or the alarm condition is rectified. The audible signal of an unacknowledged alarm should be ceased when the alarm condition is rectified.

7.3.9 An acknowledged alarm should be indicated by a steady visual indication.

7.3.10 The visual signal for an acknowledged alarm should continue until the alarm condition is




(om melding e.l.) bekrefte (å ha mottatt) 

By acknowledging an alarm , the operator lets others know that he is taking ownership of the issue. After an alarm is acknowledged, its audible notification is silenced, and other alarm actions such as flashing icons changes state to static. The alarm message, however, is still visible in the system. The message remains on the display until the value that triggered the alarm is back within normal thresholds. Alarms are neither cleared, nor reset when acknowledged.


Categories of alerts:

Alerts should be separated for the alert handling into three categories of alerts:

Category A alerts:

- where information at a task station directly assigned to the function generating the alert is necessary, as decision support for the evaluation of the alert-related condition, e.g. danger of collition and danger of grounding.

Category A alerts cannot be acknowledged at a Human Machine Interface - this fact should be clearly indicated to the user.

Category B alerts:

Category B alerts are specified as alerts where no additional information for decision support is necessary besides the information which can be presented at the display (central alarm managemen-human machine interface)

To identify the alarm on the Bridge alarm system:

2: push the corresponding alarm group icon

- the specific alarm will be displayed on top of an alarm list

- for all active alarms in the same group, alarms will be displayed in the list

- the alarm will stay red until the reason of the alarm on the corresponding equipment is removed, meaning the OOD (officer on duty) must attend the equipment generating the alarm to investigate the cause of the alarm and perform neccesary action.

3: As long as one of the alarm buttons is red, the alarm groups button on main page remain red. If an alarm is unacknowledged, the button will be blinking in bold font.

Having insight in a deeper level of user behavior than what can be observed with the bare eyes, may be a helpful asset when developing products for use in situations that are difficult to remake in a test situation.



Preliminary Recommendation

Alarm blindness

Information Overload, clutter, workload bottleneck

Exploit the ability to orient focal attention to «interesting Parts of the netural perceptual field.. Contrast based (anomaly-based processing)

acknowledging something by accident

use layout that requires the use of thinking

example: avoid final OK button in a sequence where one should think.

Information overload



Audible noise


Information overload:

-our ability to interpret meaning from the amounts of information, has expanded much more slowly, if at all. All in all, it it easier to adapt the technology to the people, rather than making people adapt to the technology.

How are people able to focus on what's interesting?

Mechanisms of human perception and cognition that enable people on focus on the relevant subset of the available data

1: perceptual organisation

2: processes of attentional control

3:anomal-based borcessing

DD. Woods et al.





Lack of sleep

insufficient rest time between periods




Ship movement

Food (timing, frequency, content and quality)

Medical conditions and illnesses

Poor quality of sleep

poor quality of rest

boring/repetitive work

Inadequate ventilation, poor lighting, excessive heat/cold, poor air exchange,

Effects of drugs, alcohol and caffeine, *

excessive work load

Poor workspace design

Inability to concentrate

slow response

loss of control of body movement

mood vhanges

heart palpitations

rapid breathing

diminished decision-making ability

poor memory

attidude changes


sudden sweating fits


loss of appetite

leg pains/cramps

Minimize fatigue inducing environmental stressors including ship movement,

excessive noise, vibration, inadequate ventilation, poor lighting, excessive heat

or cold, too much/too little humidity & poor air exchange in enclosed working

& accommodation spaces. Minimize unnecessary sustained exertion (physical

or mental) in the workplace • Design operational maintenance tasks to be rapid, safe and effective to allow

equipment & systems to achieve a specified level of performance, with the

minimum of sustained exertion

Design control centres, machinery control rooms, cargo control rooms etc,

bearing in mind the integration of people with equipment, systems and

interfaces, & the need to avoid boredom monotony, reduced vigilance and

mental overload

minimize fatigue stressors