Extending the Functionality of the Realm Gateway

The promise of 5G and Internet of Things (IoT) expects the coming years to witness substantial growth of connected devices. This increase in the number of connected devices further aggravates the IPv4 address exhaustion problem. Network Address Translation (NAT) is a widely known solution to cater to the issue of IPv4 address depletion but it poses an issue of reachability. Since Hypertext Transfer Protocol (HTTP) and Hypertext Transfer Protocol Secure (HTTPS) application layer protocols play a vital role in the communication of the mobile devices and IoT devices, the NAT reachability problem needs to be addressed particularly for these protocols. Realm Gateway (RGW) is a solution proposed to overcome the NAT traversal issue. It acts as a Destination NAT (DNAT) for inbound connections initiated towards the private hosts while acting as a Source NAT (SNAT) for the connections in the outbound direction. The DNAT functionality of RGW is based on a circular pool algorithm that relies on the Domain Name System (DNS) queries sent by the client to maintain the correct connection state. However, an additional reverse proxy is needed with RGW for dealing with HTTP and HTTPS connections. In this thesis, a custom Application Layer Gateway (ALG) is designed to enable end-to-end communication between the public clients and private web servers over HTTP and HTTPS. The ALG replaces the reverse proxy used in the original RGW software. Our solution uses a custom parser-lexer for the hostname detection and routing of the traffic to the correct back-end web server. Furthermore, we integrated the RGW with a policy management system called Security Policy Management (SPM) for storing and retrieving the policies of RGW. We analyzed the impact of the new extensions on the performance of RGW in terms of scalability and computational overhead. Our analysis shows that ALG's performance is directly dependent on the hardware specification of the system. ALG has an advantage over the reverse proxy as it does not require the private keys of the back-end servers for forwarding the encrypted HTTPS traffic. Therefore, using a system with powerful processing capabilities improves the performance of RGW as ALG outperforms the NGINX reverse proxy used in the original RGW solution

DIAMOnDS - DIstributed Agents for MObile & Dynamic Services

Distributed Services Architecture with support for mobile agents between services, offer significantly improved communication and computational flexibility. The uses of agents allow execution of complex operations that involve large amounts of data to be processed effectively using distributed resources. The prototype system Distributed Agents for Mobile and Dynamic Services (DIAMOnDS), allows a service to send agents on its behalf, to other services, to perform data manipulation and processing. Agents have been implemented as mobile services that are discovered using the Jini Lookup mechanism and used by other services for task management and communication. Agents provide proxies for interaction with other services as well as specific GUI to monitor and control the agent activity. Thus agents acting on behalf of one service cooperate with other services to carry out a job, providing inter-operation of loosely coupled services in a semi-autonomous way. Remote file system access functionality has been incorporated by the agent framework and allows services to dynamically share and browse the file system resources of hosts, running the services. Generic database access functionality has been implemented in the mobile agent framework that allows performing complex data mining and processing operations efficiently in distributed system. A basic data searching agent is also implemented that performs a query based search in a file system. The testing of the framework was carried out on WAN by moving Connectivity Test agents between AgentStations in CERN, Switzerland and NUST, Pakistan.Comment: 7 pages, 4 figures, CHEP03, La Jolla, California, March 24-28, 200

The Relentless Pursuit Of Construct Validity In The Design Of Employment Interviews

The construct validity of employment interviews is the greatest challenge faced by employment interview researchers. In this paper, we discuss the theoretical and methodological issues which have an influence upon the construct validity ofemployment interviews.Wepay special attention to issues that emerge at the conceptual development and design stage of interviews. So far, the structuring of employment interviews has been the primary method of improving construct validity. We argue that construct validity can be further improved by bringing theoretical rigor in the design of interviews. For this purpose, we propose steps to reframe the interview dimensions in theoretical frameworks of job performance, to explicate the nomological network of interview constructs, to clarify the validation strategy, and to improve the questions and assessment keys. In the end, we provide an example to illustrate the application of these steps

The Relentless Pursuit Of Construct Validity In The Design Of Employment Interviews

The construct validity of employment interviews is the greatest challenge faced by employment interview researchers. In this paper, we discuss the theoretical and methodological issues which have an influence upon the construct validity ofemployment interviews.Wepay special attention to issues that emerge at the conceptual development and design stage of interviews. So far, the structuring of employment interviews has been the primary method of improving construct validity. We argue that construct validity can be further improved by bringing theoretical rigor in the design of interviews. For this purpose, we propose steps to reframe the interview dimensions in theoretical frameworks of job performance, to explicate the nomological network of interview constructs, to clarify the validation strategy, and to improve the questions and assessment keys. In the end, we provide an example to illustrate the application of these steps

The relentless pursuit of construct validity: Why employment interviews predict job performance?

Employment interviews are one of the most frequently researched areas in the human resources management research (Buckley, Norris, & Wiese, 2000). Over the last eighty years, the employment interview research has gone through several phases. Fifty years ago, researchers seemed to have little hope for the criterion-related validity of employment interviews (Ulrich & Trumbo, 1965; Wagner, 1949). However, in the 90s several methodological advancements furnished evidence to support the criterion validity of employment interviews (Huffcutt & Arthur, 1994; McDaniel, Whetzel, Schmidt, & Maurer, 1994). Structuring interviews has been the major antecedent of increasing validity of interviews since then. The patterned behavior description interviews (Janz, 1982) and the situational interviews (Latham, Saari, Pursell, & Campion, 1980) have become the two most widely used techniques of conducting structured employment interviews. With all these advancements, any doubts regarding the criterion validity of structured employment interviews have been nullified. This development has freed researchers to turn their attention toward a newer set of issues in this line of research.One new question attracting considerable attention from researchers is "why do employment interviews predict performance?" On the surface it seems to be a straightforward question with an easy answer. However, research so far has provided equivocal results regarding the construct validity of employment interviews. My three-essay dissertation focuses on resolving those issues that plague the construct validity of employment interviews. In the first essay, I review the existing research that is concerned with the constructs underlying employment interviews. I examine various issues that emerge during the stages of interview design, administration, assessment, and analysis. I pay special attention to the theoretical issues that hinder construct validity evidence. More specifically, I highlight how grounding employment interviews in the theory of job performance (Campbell, McCloy, Oppler, & Sager, 1993) might positively influence construct validation efforts. I also stress the need to view an employment interview as a predictor method (rather than as a predictor construct) and emphasize the unique construct validation challenges that any predictor method (e.g., assessment center) faces. The purpose of the first study is to lay out a comprehensive framework that guides future research.Many researchers have shown that different types of interview questions (e.g., behavioral questions, situational questions, and general questions) tap different constructs (e.g., Conway & Peneno, 1999). My second essay explores the construct validity of past behavior description interviews (PBDI). To date several studies have explored the constructs underlying PBDI questions. Social skills, experience, motivation, and intelligence have been proposed as some of the constructs that explain why PBDI questions predict performance (O'Leary, 2004). However, there seems to be little consensus on the specific constructs that are tapped by the different interview types. PBDIs are designed on the premise that apattern of past behaviors is a best predictor of future behaviors. The structuring efforts are aimed at ensuring that interview responses only assess the quality of past behaviors, and that no other biases (e.g., likeability of a candidate, personal biases of an interviewer, and impression management by a candidate) influence the evaluation of a candidate. If PBDI questions only measure the quality of past behaviors then the assessment of candidates based on oral interviews and the assessment based on written responses should be the same. I challenge this assertion and argue that an interview is primarily a social interaction process. Thus, even highly structured interviews, such as PBDI, measure additional constructs such as extraversion, emotional stability, self-esteem, and self-efficacy.The third study explores the construct validity and incremental validity of general interview questions. Despite research evidence that supports the use of PBDI- and SI-type questions, managers continue using general questions in actual job interviews. In this study, I propose how to make the general interview questions more effective. I propose that researchers can increase the validity of general questions when they have an a priori understanding of underlying constructs, they ground the interview design in a relevant theory, and they make the intended dimensions transparent to the candidates. I argue that general type of questions can assess certain constructs such as values and personality, and thus add incremental validity to the interview process. In addition, by incorporating general questions in the interview design, interviews achieve the flexibility desired by practitioners and increase their comfort level with the interview process

Use of Zinc and ORS in Home Management of Diarrhea: Knowledge of Mothers attending a Tertiary Care Hospital

Background: Diarrhea is the second leading cause of mortality in children below 5 years of age in Pakistan. Use of Zinc and ORS has been proven in clinical trials to be beneficial in reducing morbidity and mortality. Poor knowledge regarding home management of diarrhea leads to mortality due to severe dehydration. The objective of this study was to assess the level of knowledge of mothers of under five-year-old children regarding, diarrheal home management in Cantonment General Hospital, Rawalpindi.Material and Methods: This was an observational cross-sectional study carried out at Department of Pediatrics, Cantonment General Hospital, Rawalpindi, from 1st August, 2017 to 31st January, 2018. About 400 mothers of under five-year-old children, coming to the outpatient department of the hospital were enrolled in this study. A self-designed structured and validated questionnaire was used to assess the level of knowledge of mothers regarding home management of diarrhea using Oral Rehydration Solution (ORS) and Zinc. Data was analyzed using SPSS version 23 with a p value < 0.05 considered statistically significant.Results: About 91% (n=364) of mothers had awareness regarding use of ORS as a means of diarrheal home management. Regarding level of knowledge variable results were found. A good percentage of mothers had knowledge of the purpose of ORS use (78.3%), administration (60%) and initiation of ORS (68%), but only 20.8% mothers rightly answered the timing of ORS administration. Mothers knowledge about the use of zinc, daily administration and duration of administration (10-14 days) was 38.8% ,20.5% and 17.3% respectively. Mothers who were more educated especially secondary and above and of the age group 22-31, had better awareness of ORS than others, as P value is less than 0.05. Among mothers who were aware of the use of ORS, only 41.8% of them were also aware of the use of zinc.Conclusion: A high awareness level regarding ORS use in mothers was reflected fairly in terms of purpose, administration and initiation of ORS but the kn

Correlating CT Chest with RT-PCR in Diagnosing COVID-19: Experience at a Tertiary Health Care Hospital in Pakistan

Objective: To establish the accuracy of computed tomography(CT) chest in the diagnosis of COVID-19 pneumonia by taking reverse transcriptase-polymerase chain reaction(RT-PCR) as a reference standard and to analyze discordant CT chest and RT-PCR results. Materials and Methods: A retrospective cross-sectional study of patients presented to a tertiary health care hospital in Punjab, Pakistan for CT examination with suspicion of COVID-19 from April 1, to June 30, 2020. Each CT chest was categorized as positive/negative for COVID-19 pneumonia and the results were compared with the RT-PCR test. Discordant CT chest and PCR results were also investigated. Results: The study population had a mean age of 48 years ± 6.6 years with 54.5% males and 45.4% females. Sensitivity(Sn), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of CT in diagnosing COVID-19 pneumonia taking RT- PCR as the gold standard was 92.5%, 46.6%%, 82.2%, 70%, and 80% respectively. Conclusion: CT chest has high sensitivity but modest specificity in the diagnosis of COVID-19 pneumonia. It can be employed as an adjunctive screening and diagnostic test for early diagnosis of disease in places where disease prevalence is high

Comparison of intra-articular lidocaine versus intravenous sedative and analgesic for reduction of anterior shoulder dislocation in terms of mean pain reduction using vas score

INTRODUCTION: The most common dislocation presenting to emergency department is anterior shoulder dislocation. Posterior dislocations and inferior dislocations are rare. Dislocations of the anterior shoulder mostly occur with the position of the arm is abducted and externally rotated. This results in injury of the humeral head, labrum, capsuloligamentous structures and glenoid. Such patients experience severe pain, therefore prompt reduction is necessary to ameliorate the pain. Intravenous analgesia combined with sedation or intra-articular lidocaine injection can be used for closed reduction of anterior shoulder dislocation. Due to its side effects, Intra-articular lidocaine (IAL) is recommended for use as a probable alternative to intravenous sedation-analgesia especially for patients with contraindication to intravenous sedation-analgesia. OBJECTIVE: To compare intra-articular lidocaine versus intravenous sedative and analgesic for management of anterior shoulder dislocation in terms of mean pain using VAS during reduction of shoulder joint. STUDT DESIGN:   Randomized controlled trial (RCT). SETTING: Removed for blind review DURATION: 6 months (November 22nd, 2017 to May 21st, 2018) SAMPLE SIZE: 60 patients (30 in each group) RESULTS: We included sixty patients in my study. 19 (31.7%) were females and 41 (68.3%) were male patients. Out of all the patients 38 (63.3%) had right sided shoulder dislocation, while the rest 22 (36.7%) patients had left sided shoulder dislocation. Patients mean age was 33.27±10.535 years and mean pain score of all the patients was 4.966±1.930. The mean pain score in Group A was 4.200±1.648, while the mean pain score in Group B was 5.733±1.910 (p value = 0.002. Stratification was done according to gender and age group of the patients, and post-stratification t-test was applied. CONCLUSION:   Intra-articular lidocaine is better option in pain control during reduction of anterior shoulder dislocation. KEY WORDS: Intra venous analgesia, Intra-articular lidocaine, shoulder dislocation

Cloning and expression of hepatitis B surface gene in E. coli

Background: Hepatitis B virus (HBV) is among the smallest DNA viruses resulting in ~800,000 deaths each year. Pakistan is considered a country affected by HBV. In Pakistan, the most dominant genotype is D. HBV is an enveloped virus of 3.2 kb. The study's goal was to express hepatitis B surface antigen in a bacterial host to produce a recombinant protein.Method: Blood samples were collected in EDTA coated vacutainer from patients after their consent. DNA was extracted from serum through the phenol-chloroform method; Hepatitis B surface gene was cloned in TA cloning vector, subclone in pET 28a expression vector. An expression vector containing the Surface gene was then transformed into a competent bacterial host BL21 and inducted with IPTG at 0.1-0.2mM concentration for expression. The expressed proteins (soluble and pellet form) were analyzed on SDS PAGE.Results: Hepatitis B Surface gene of 681bp after PCR were detected under UV light then successfully cloned and subcloned in pET 28 expression vector. The restricted fragment indicating the gene of interest was 681bp when analyzed on 1.2% Agarose gel under UV light. The required protein of 25kDa was obtained in soluble form when detected on 12% SDS PAGE after staining with Coomassie Blue dye.Conclusion: Hepatitis B surface gene was successfully expressed in both insoluble and pellet forms using E.coli. The expression of surface protein needs to maximize through optimizing conditions to be used as potent candidate for vaccine production to prevent hepatitis B infection.Keywords: Hepatitis B virus; Surface gene; Cloning vector; pET expression vector