阅读说明：本技术 基于网络爬虫的招聘信息可视化分析系统 (Recruitment information visualization analysis system based on web crawler ) 是由 郭盛 于 2020-02-18 设计创作，主要内容包括：本发明公开了一种基于网络爬虫的招聘信息可视化分析系统,包括：数据处理模块包括：数据采集单元；数据提取单元；数据清洗单元用于过滤重复信息形成一级筛选数据集；求职者检索模块包括：检索输入单元；信息匹配单元用于筛选一级筛选数据集中满足检索信息要求的招聘信息形成二级筛选数据集；目的地识别单元；居住地限定单元；要求输入单元；信息筛选单元用于根据要求信息筛选出符合要求信息的招聘信息形成三级筛选数据集；可视化显示模块,用于依据目的地信息将三级筛选数据集中的招聘信息显示于电子地图上。本发明具有能够在满足搜索者(求职者)满足搜索要求的同时,按照到达目的地方便程度个性化、可视化推荐展示的有益效果。(The invention discloses a recruitment information visualization analysis system based on web crawlers, which comprises the following steps: the data processing module comprises: a data acquisition unit; a data extraction unit; the data cleaning unit is used for filtering repeated information to form a primary screening data set; the job seeker retrieval module comprises: a search input unit; the information matching unit is used for screening the recruitment information meeting the retrieval information requirement in the primary screening data set to form a secondary screening data set; a destination identifying unit; a residence defining unit; a request input unit; the information screening unit is used for screening the recruitment information meeting the requirement information according to the requirement information to form a three-level screening data set; and the visual display module is used for displaying the recruitment information in the three-level screening data set on the electronic map according to the destination information. The invention has the advantages that the invention can meet the search requirement of a searcher (job seeker), and meanwhile, the invention can recommend and display the information individually and visually according to the convenience degree of the destination.)

1. Recruitment information visualization analysis system based on web crawlers is characterized by comprising:

a data processing module, comprising:

the data acquisition unit is used for acquiring a target data source on a human resource website by adopting a web crawler technology;

the data extraction unit is connected with the data acquisition unit and is used for extracting recruitment data in the target data source to form a recruitment data set, the recruitment data set comprises a plurality of pieces of recruitment information, each piece of recruitment information comprises display information, and the display information comprises at least one of company properties, position salaries and working places, a company name and a position category;

the data cleaning unit is connected with the data extraction unit, a position category classification table is prestored in the data cleaning unit, the position category names are unified by the data cleaning unit according to the prestored position category classification table, and then repeated information is filtered to form a primary screening data set, wherein if the display information comprises a work place, the repeated information is recruitment information with the same company name, work place and position category, and if the display information does not comprise the work place, the repeated information is recruitment information with the same company name and position category;

a job seeker retrieval module, comprising:

the system comprises a retrieval input unit, a search input unit and a search processing unit, wherein the retrieval input unit comprises a company name input box, a position salary input box, a company property input box, a work place input box and a position category input box, the company name input box is used for a searcher to input retrieval information, the position salary input box comprises a frame body used for inputting a salary upper limit and a frame body used for inputting a salary lower limit, the company property input box comprises defined keywords of which the options are private enterprises, national enterprises, foreign enterprises and public institutions, the work place input box comprises defined keyword options of provinces, cities and detailed addresses which are arranged from large to small according to included relations, the position category input box is used for inputting position category names, and each input box also comprises unlimited defined keyword options;

the information matching unit is connected with the retrieval input unit and the data cleaning unit and is used for acquiring retrieval information input by a searcher and screening recruitment information meeting the requirement of the retrieval information in the primary screening data set to form a secondary screening data set;

the destination identification unit is connected with the information matching unit and used for identifying the geographic position corresponding to the recruitment information in the secondary screening data set as destination information;

a residence defining unit for the retriever to input residence information;

the system comprises a request input unit and a display unit, wherein the request input unit comprises a vehicle limiting frame and a display request limiting frame, the vehicle limiting frame is used for inputting request information, the vehicle limiting frame comprises public transportation, self-driving, a taxi and unlimited defined keyword options, the display request limiting frame comprises the defined keyword options of time requirements, journey requirements and charging requirements, and the priority of the vehicle limiting frame is superior to that of the display request limiting frame;

the information screening unit is connected with the destination identification unit, the residence limiting unit and the requirement input unit and is used for screening the recruitment information meeting the requirement information according to the destination information and the residence information and the requirement information to form a three-level screening data set;

and the visual display module is connected with the information screening unit and is used for displaying the recruitment information in the three-level screening data set on the electronic map according to the destination information.

2. The web crawler-based recruitment information visualization analysis system of claim 1 wherein the presentation information further comprises a publication time and the data cleansing unit further comprises eliminating recruitment information having a publication time longer than one month before filtering the repetitive information.

3. The web crawler-based recruitment information visualization analysis system of claim 1 wherein each recruitment information further comprises qualifying information comprising at least one of age definitions, height definitions, weight definitions, political face definitions, work experience definitions, gender definitions, academic definitions, professional definitions, foreign language level definitions, computer level definitions;

the retrieval input unit also comprises an age input box, a height input box, a weight input box, a political face input box, a work experience input box, a sex input box, a study history input box, a professional input box, a foreign language level input box and a computer level input box which are used for a retriever to input basic information;

the information matching unit eliminates the recruitment information of which the limited information is not matched with the basic information of the retriever in the recruitment information in the primary screening data set before calculating the similarity of the recruitment information in the primary screening data set.

4. The web crawler-based recruitment information visualization analysis system as claimed in claim 3, wherein the identification of the geographic location corresponding to the recruitment information in the secondary screening dataset by the destination identification unit as the destination information specifically comprises:

judging whether the work place is a specific address or not, and if so, taking the work place as destination information;

if not, acquiring a specific address of the company according to the name of the company, judging whether the address of the company belongs to the work place, and if so, taking the address of the company as destination information;

and if not, taking the optimal place in the representative range of the working place as destination information, marking the optimal place as fuzzy information, and taking the correspondingly screened recruitment information as fuzzy recruitment information.

5. The web crawler-based recruitment information visualization analysis system of claim 4 wherein the fuzzy recruitment information display in the tertiary screening dataset is distinct from the display of other recruitment information.

6. The web crawler-based recruitment information visualization analysis system of claim 5 wherein other recruitment information is displayed in a gradual manner of compliance.

Technical Field

The invention relates to the technical field of recruitment information visualization analysis. More particularly, the invention relates to a recruitment information visualization analysis system based on web crawlers.

Background

With the development of the internet, online job hunting and recruitment become the mainstream job hunting and recruitment approaches, and an online recruitment system bridges job seekers and personnel units/guys, thereby providing convenience for both parties to the maximum extent. However, job seekers are faced with a huge amount of job site information, and they may spend a lot of time and find suitable job information. The website recruitment system issues recruitment information to users according to user descriptions, and when the website recruitment system issues the recruitment information to the users, the website recruitment system mostly displays the recruitment information in a list character mode, so that visual expression is not clear enough, and for job seekers with fixed residences, the personalized requirements of the job seekers are met, and the problem that personalized and visual recommendation and display are needed to be solved at present according to the convenience degree of reaching a destination is solved while the search requirements are met.

The applicant does not know how to select the job best suitable for himself in the dazzling recruitment information, so that the massive recruitment information needs to be analyzed more deeply and at a higher level. The system crawls massive recruitment information on the network through a web crawler technology, performs related data cleaning work on the information, and performs visual analysis on the cleaned data. The functions of classified checking, fuzzy query and multi-condition combined query of the crawled recruitment information, crawling of the recruitment information according to keywords and the like are realized. With the gradual maturity of big data analysis technology, massive data can be managed, sorted and analyzed within a reasonable time, so that hidden association rules among data are discovered and future development trends are predicted.

Disclosure of Invention

An object of the present invention is to solve at least the above problems and to provide at least the advantages described later.

It is still another object of the present invention to provide a web crawler-based recruitment information visualization analysis system, which is capable of satisfying the search requirements of the searcher (job seeker) and simultaneously performing personalized and visual recommendation display according to the convenience of reaching the destination.

To achieve these objects and other advantages in accordance with the present invention, there is provided a web crawler-based recruitment information visualization analysis system comprising:

a data processing module, comprising:

the data acquisition unit is used for acquiring a target data source on a human resource website by adopting a web crawler technology;

the data extraction unit is connected with the data acquisition unit and is used for extracting recruitment data in the target data source to form a recruitment data set, the recruitment data set comprises a plurality of pieces of recruitment information, each piece of recruitment information comprises display information, and the display information comprises at least one of company properties, position salaries and working places, a company name and a position category;

the data cleaning unit is connected with the data extraction unit, a position category classification table is prestored in the data cleaning unit, the position category names are unified by the data cleaning unit according to the prestored position category classification table, and then repeated information is filtered to form a primary screening data set, wherein if the display information comprises a work place, the repeated information is recruitment information with the same company name, work place and position category, and if the display information does not comprise the work place, the repeated information is recruitment information with the same company name and position category;

a job seeker retrieval module, comprising:

the system comprises a retrieval input unit, a search input unit and a search processing unit, wherein the retrieval input unit comprises a company name input box, a position salary input box, a company property input box, a work place input box and a position category input box, the company name input box is used for a searcher to input retrieval information, the position salary input box comprises a frame body used for inputting a salary upper limit and a frame body used for inputting a salary lower limit, the company property input box comprises defined keywords of which the options are private enterprises, national enterprises, foreign enterprises and public institutions, the work place input box comprises defined keyword options of provinces, cities and detailed addresses which are arranged from large to small according to included relations, the position category input box is used for inputting position category names, and each input box also comprises unlimited defined keyword options;

the information matching unit is connected with the retrieval input unit and the data cleaning unit and is used for acquiring retrieval information input by a searcher and screening recruitment information meeting the requirement of the retrieval information in the primary screening data set to form a secondary screening data set;

the destination identification unit is connected with the information matching unit and used for identifying the geographic position corresponding to the recruitment information in the secondary screening data set as destination information;

a residence defining unit for the retriever to input residence information;

the system comprises a request input unit and a display unit, wherein the request input unit comprises a vehicle limiting frame and a display request limiting frame, the vehicle limiting frame is used for inputting request information, the vehicle limiting frame comprises public transportation, self-driving, a taxi and unlimited defined keyword options, the display request limiting frame comprises the defined keyword options of time requirements, journey requirements and charging requirements, and the priority of the vehicle limiting frame is superior to that of the display request limiting frame;

the information screening unit is connected with the destination identification unit, the residence limiting unit and the requirement input unit and is used for screening the recruitment information meeting the requirement information according to the destination information and the residence information and the requirement information to form a three-level screening data set;

and the visual display module is connected with the information screening unit and is used for displaying the recruitment information in the three-level screening data set on the electronic map according to the destination information.

Preferably, the display information further includes a publication time, and the data cleansing unit further includes a recruitment information eliminating the publication time longer than one month before filtering the repeated information.

Preferably, each recruitment information further comprises restriction information, the restriction information comprising at least one of age restriction, height restriction, weight restriction, political face restriction, work experience restriction, gender restriction, academic restriction, professional restriction, foreign language level restriction, computer level restriction;

the retrieval input unit also comprises an age input box, a height input box, a weight input box, a political face input box, a work experience input box, a sex input box, a study history input box, a professional input box, a foreign language level input box and a computer level input box which are used for a retriever to input basic information;

the information matching unit eliminates the recruitment information of which the limited information is not matched with the basic information of the retriever in the recruitment information in the primary screening data set before calculating the similarity of the recruitment information in the primary screening data set.

Preferably, the identifying the geographic location corresponding to the recruitment information in the secondary screening dataset as the destination information by the destination identifying unit specifically comprises:

judging whether the work place is a specific address or not, and if so, taking the work place as destination information;

if not, acquiring a specific address of the company according to the name of the company, judging whether the address of the company belongs to the work place, and if so, taking the address of the company as destination information;

and if not, taking the optimal place in the representative range of the working place as destination information, marking the optimal place as fuzzy information, and taking the correspondingly screened recruitment information as fuzzy recruitment information.

Preferably, the display of the fuzzy recruitment information in the tertiary screening dataset is distinct from the display of other recruitment information.

Preferably, the other recruitment information is displayed gradually according to the degree of compliance.

The invention at least comprises the following beneficial effects:

the system can meet the search requirement of a searcher (job seeker), and meanwhile, the system can recommend the display in a personalized and visual mode according to the convenience degree of the destination, and specifically comprises the following steps: the data cleaning unit, the information matching unit and the information screening unit are matched to gradually realize three-level screening, invalid repeated data are removed in the first step, information data which do not meet the requirement of a searcher are removed in the second step, the validity of output data is effectively improved, further, the relationship between a destination and a residence is judged in a personalized manner, and the third-level screening is carried out, so that the personalized requirement of the fixed searcher in the residence is effectively met; the geographical position is used as a link, map visualization is realized, and a clearer spatial cognitive framework is provided for understanding information.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

Fig. 1 is a block diagram illustrating a structure of a web crawler-based recruitment information visualization analysis system according to one embodiment of the present invention.

Detailed Description

The present invention is further described in detail below with reference to examples so that those skilled in the art can practice the invention with reference to the description.

As shown in fig. 1, the present invention provides a recruitment information visualization analysis system based on web crawlers, comprising:

a data processing module, comprising:

the data acquisition unit is used for acquiring a target webpage on a human resource website by adopting a web crawler technology to form a target data source;

the data extraction unit is connected with the data acquisition unit and is used for extracting recruitment data in the target data source to form a recruitment data set, the recruitment data set comprises a plurality of pieces of parallel recruitment information, each piece of recruitment information comprises display information, and the display information comprises at least one of company properties, position salary and working place, a company name and a position category;

the data cleaning unit is connected with the data extraction unit, pre-stores a position category classification table in the data cleaning unit, classifies the position categories into a position category detailed category, a position category minor category and a position category major category from small to large according to the included relationship, and the limitation of the position categories can refer to the current classification rule specifically, wherein one of the positions is shown in the following table 1, the position category detailed category is recorded in the position category classification table, the position category names are unified by the data cleaning unit according to the pre-stored position category classification table, and then repeated information is filtered to form a primary screening data set, wherein if the display information comprises a work place, the repeated information is recruitment information with the same company name, work place and position category, and if the display information does not comprise the work place, the repeated information is recruitment information with the same company name and position category;

TABLE 1 job Classification

A job seeker retrieval module, comprising:

the system comprises a retrieval input unit, a search input unit and a search processing unit, wherein the retrieval input unit comprises a company name input box, a position salary input box, a company property input box, a work place input box and a position category input box, the company name input box is used for inputting a company name, the position salary input box comprises a box body for inputting a salary upper limit and a box body for inputting a salary lower limit, the company property input box comprises defined keywords of which the options are private enterprises, national enterprises, foreign enterprises and public institution, the work place input box comprises defined keyword options of provinces, cities and detailed addresses which are arranged from large to small according to included relations, the position category input box is used for inputting position category names, and each input box also comprises unlimited defined keyword options;

the information matching unit is connected with the retrieval input unit and the data cleaning unit and is used for acquiring retrieval information input by a retriever, screening recruitment information meeting the requirement of the retrieval information in the primary screening data set to form a secondary screening data set, and the acquired retrieval information can be specifically shown in the following table 2:

table 2 search information

Company name	Nature of company	Position salary	Work place	Job category
					Without limitation	National rabbet	Without limitation	Nanjing	Water treatment engineer

According to table 2, the specific screening of the recruitment information meeting the requirement of the retrieval information in the primary screening dataset is as follows: screening and obtaining recruitment information which meets the requirements that the company is a national enterprise, the work place is Nanjing and the job category is a water treatment engineer;

the destination identification unit is connected with the information matching unit and used for identifying the geographic position corresponding to the recruitment information in the secondary screening data set as destination information;

a residence defining unit for the retriever to input residence information;

the requirement input unit comprises a transportation limiting frame and a display requirement limiting frame, wherein the transportation limiting frame is used for inputting requirement information, the transportation limiting frame comprises public transportation (buses and subways), self-driving, taxis (comprising windward vehicles, taxi-taking and the like in the prior sense, the charging is uniformly calculated according to the prior charging standard of the taxis), unlimited defined keyword options, the display requirement limiting frame comprises the defined keyword options of time requirements, journey requirements and charging requirements, the priority of the transportation limiting frame is superior to that of the display requirement limiting frame, namely whether the limiting requirements of the display requirement limiting frame are met under the condition that the transportation is limited in the transportation limiting frame is calculated, and the requirement information can be specifically shown in the following table 3:

TABLE 3 request information

The information screening unit is connected with the destination identification unit, the residence limiting unit and the requirement input unit and is used for screening the recruitment information meeting the requirement information according to the destination information and the residence information and the requirement information to form a three-level screening data set;

and the visual display module is connected with the information screening unit and is used for displaying the recruitment information in the three-level screening data set on the electronic map according to the destination information, specifically, the corresponding place of the recruitment information in the three-level screening data set on the electronic map is positioned and displayed according to the destination information, the external display form can be specifically an icon, and the hidden information corresponding to the icon, such as the specific content of the recruitment information, can be displayed by clicking the icon.

In the above technical solution, the basis of visual analysis of recruitment information is data, and such data exists in various large human resource websites, for example, an intelligent recruitment network, a hunting network, and the like, the recruitment information contained in the target webpage is an original unstructured webpage, which contains irrelevant information such as advertisements, and unrelated information can be removed by using a row block distribution function method, and then structured data is accurately extracted from the unstructured data to form a recruitment data set, wherein the company property includes private enterprises, national enterprises, foreign enterprises, public institutions, and absence, the work place can be a specific place (e.g., XX street number, i.e., a specifically positioned place), and can also be a wide-range limited place (e.g., XX market), and the data cleaning unit unifies and specifically defines pre-stored job category names according to a category classification table: determining the similarity between the job category name and each name in the job category subclass, and determining the name of the job category subclass with the highest similarity as the job category name, wherein the job category subclass is obtained specifically as follows: collecting a target data source on a human resource website by adopting a web crawler technology at regular intervals, extracting job category names in the target data source, removing the job category names which are the same as the originally existing job category subclasses to obtain a pre-screening job category classification set, judging the similarity between the job names in the pre-screening job category set and each name in the job category subclasses, manually judging whether the job names in the pre-screening job category set are new jobs or not according to the similarity from low to high, if so, supplementing the job names to a job category classification list, and if not, deleting the job names, and stopping after judging that the job names are not found for the first time; screening out the recruitment information meeting the requirement information according to the requirement information to form a three-level screening data set, which specifically comprises the following steps:

when the required information is the required information 1, judging the time for arriving at the destination from the residence in one way under the condition that the taxi is taken as a transportation means, and judging whether the time is shorter than 1h, if so, forming one of three levels of screening data sets by the recruitment information corresponding to the destination, wherein the judgment of the time is carried out according to normal traffic;

when the required information is the required information 2, judging the lowest cost for arriving at the destination from the residential area in one way under the condition of not limiting the transportation means, and judging whether the cost is less than 10 yuan, if so, forming one of three levels of screening data sets by the recruitment information corresponding to the destination, wherein the judgment of the lowest cost under the condition of not limiting the transportation means is the result of comparison after the judgment in sequence under the three transportation conditions;

when the requirement information is requirement information 3, judging whether a condition that public transportation is used as a vehicle exists or not, wherein the condition that public transportation is used as the vehicle specifically can be set to be that subway or bus exists, and the walking distance of people is less than a preset distance (specifically can be 2 km); in the using process, a first-level screening data set is obtained by using the data processing module, a third-level screening data set is obtained by using the job seeker retrieval module, and the recruitment information corresponding to the third-level screening data set is displayed by using the visual display module; by adopting the technical scheme, the personalized and visual recommendation display according to the convenience degree of the destination can meet the search requirement of a searcher (job seeker), and specifically comprises the following steps: the data cleaning unit, the information matching unit and the information screening unit are matched to gradually realize three-level screening, invalid repeated data are removed in the first step, information data which do not meet the requirement of a searcher are removed in the second step, the validity of output data is effectively improved, further, the relationship between a destination and a residence is judged in a personalized mode, third-level screening is carried out, and the personalized requirement of the fixed searcher in the residence is effectively met.

In another technical scheme, the display information further comprises release time, and the data cleaning unit further comprises recruitment information with the release time longer than one month before filtering the repeated information. By adopting the scheme, invalid information is further eliminated.

In another technical scheme, each piece of recruitment information further comprises definition information, wherein the definition information comprises at least one of age definition, height definition, weight definition, political face definition, work experience definition, gender definition, academic definition, professional definition, foreign language level definition and computer level definition;

the retrieval input unit further comprises an age input box, a height input box, a weight input box, a political face input box, a work experience input box, a sex input box, a study history input box, a professional input box, a foreign language level input box and a computer level input box, wherein the age input box is used for the retriever to input the age; the height input box is used for the searcher to input the height; the weight input box is used for the searcher to input weight; the political face input box is used for a searcher to input political faces and specifically comprises a party and a crowd; the work experience input box is used for a searcher to input work experience, and can be divided according to 0 year, less than 1 year, 1-3 years, 3-5 years, 5-7 years, 7-9 years and more than 10 years; the gender input box is used for the searcher to input gender, and specifically comprises a male and a female; the study history input box is used for a searcher to input a study history, which specifically comprises junior high school, senior high school, major, the subject, a master and a doctor; the professional input box is used for a searcher to input a professional; the foreign language level input box is used for the searcher to input the foreign language level; the computer level input box is used for a searcher to input the computer level, and all input boxes of the search input unit also comprise unselected defined keywords;

before calculating the similarity with the recruitment information in the primary screening data set, the information matching unit eliminates the recruitment information of which the limited information is not matched with the basic information of the retriever in the recruitment information in the primary screening data set, namely whether the basic information of the matched retriever meets the requirement of the limited information in the recruitment information. By adopting the scheme, the effective recruitment information is further screened for the searcher.

In another technical solution, the identifying, by the destination identifying unit, the geographic location corresponding to the recruitment information in the secondary screening data set as the destination information specifically includes:

judging whether the work place is a specific address (the specific address is an address which can be positioned to a specific place, such as a house number, a building name and the like, and can be positioned to a specific position), and if so, taking the work place as destination information;

if not, acquiring a specific address of the company according to the name of the company, judging whether the address of the company belongs to the work place, if so, taking the address of the company as destination information, if not, the work place is an upper address of the specific address, summarized into a larger range, such as Nanjing presented in Table 2, judging whether the address of the company belongs to the work place, specifically judging whether the address of the company is located in a range included by the work place, if so, determining that the address of the company belongs to the work place, and if so, determining that the address of the company does not belong to the work place;

if not, taking the optimal place in the working place representative range as destination information, marking the optimal place as fuzzy information, and taking the correspondingly screened recruitment information as fuzzy recruitment information, wherein the optimal place is determined according to the defined keyword option in the display requirement limiting frame, if the option is time, taking the place with the shortest time to reach the residence place under the set transportation means as the optimal place, if the option is a route, taking the place with the shortest route to reach the residence place under the set transportation means as the optimal place, and if the option is charging, taking the place with the lowest charge to reach the residence place under the set transportation means as the optimal place;

when the destination information is fuzzy information and the request information is request information 1, judging the shortest time for reaching the destination range (optimal place) from the residential place in one way under the condition that a taxi is taken as a transportation means, judging whether the time is shorter than 1h, and if so, constructing one of three levels of screening data sets by the recruitment information corresponding to the destination, wherein the judgment of the time is carried out according to normal traffic. By adopting the scheme, when the destination information is determined, the work place is taken as the leading factor, the relation between the work place and the company address is comprehensively considered, and under the condition of improving the accuracy of determining the destination information, fuzzy information is allowed to exist, so that missing items in retrieval are effectively avoided.

In another technical scheme, the display of the fuzzy recruitment information in the third-level screening dataset is different from the display of other recruitment information. By adopting the scheme, the fuzzy recruitment information can be distinguished and displayed in different modes of different icons, different colors, different sizes and the like, so that a searcher can distinguish the fuzzy recruitment information more intuitively.

In another technical scheme, other recruitment information (different from fuzzy recruitment information in the three-level screening dataset) is displayed according to the gradual change of the coincidence degree. By adopting the scheme, the conformity degree specifically refers to the degree meeting the required information, and if the time requirement is set in the display requirement limiting frame, the display is gradually changed according to the time length; if the display requirement limiting frame is internally set with the route requirement, gradually displaying according to the route length; if the charging requirement is set in the display requirement limiting frame, the charging requirement is displayed gradually according to the charging height.

While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.