Conventional Port Research Articles

Well Matched Electromagnetic Boundary in FDTD-PIC for Charged Particle Penetration

The authors address the Matched Phase Velocity method for bounding an electromagnetic (EM) domain in the MAGIC finite difference-time domain (FDTD) particle-in-cell (PIC) EM code. Reflected power is shown to be reduced 18 dB compared to the conventional port treatment. Boundary quality is preserved under penetration by charged particles. fields. This approach is versatile and provides self consistent interaction between particles and fields. The MAGIC software includes a broad variety of boundary and material properties as well as particle and field algorithms. We will make use of only a selected subset to illustrate the behavior of the improved CMPV approach. The centered MPV method for bounding an electromagnetic domain will be shown to be effective in reducing unwanted boundary reflections in the MAGIC EM code and has the pleasing symmetry of application that waves may be injected and removed from the simulation via the same numerical methodology, and does not exhibit the unstable behavior of other ABC methods when penetrated by charged particles.

스파크점화기관에서 흡기제어 방식이 부분부하 성능에 미치는 영향(1) - 스로틀링과 마스킹의 비교

Abstract : This paper is the first investigation on the effect of flow control methods on the part load performance in a spark ignition engine. For comparison of the methods, two control devices, port throttling and masking, were applied to a conventional engine without any design change of the intake port. Steady flow evaluation shows that steady flow rates per unit opening area and swirl ratio are very low compared with the port throttling and saturated from mid-stage valve lift, however, swirl increases slightly as the lift is higher in case of 1/4 masking control. In the part load performance, the effect of simple port throttling on lean misfire limit expansion is limited and insufficient; on the other hand a masking improves the limit considerably without any port modification for increasing swirl. Also the results show that the intake flow control improves the combustion with following two mechanisms: stratification induced by the combination of the flow pattern and the fuel injection timing attribute to ignition ability and the intensified flow ensure fast burn. In addition fuel consumption reduces under the flow controls and the reduction rate is different according to the operation conditions and control methods. At the Stoichiometric and/or low speed and low load the throttling method is more advantageous; however vice versa at lean and high load condition. Finally, the throttling is more efficient for HC reduction than masking, on the other side the NOx emissions increase under the masking and decrease under the port throttling compared with conventional port scheme.

Single-Site Laparoscopic Radical Hysterectomy Using Conventional Ports and Instruments

Study ObjectiveTo study the technical feasibility of performing a radical hysterectomy via laparoscopic single-site surgery LESS. PatientA 45-year-old woman with cervical cancer stage IA2. InterventionBiopsy report showed invasive keratinizing squamous cell carcinoma, grade II. We duplicated the steps of our “Pune technique” of laparoscopic radical hysterectomy to perform a radical hysterectomy via laparoscopic single-site surgery using conventional ports and instruments. Measurements and Main ResultsOncologic clearance was comparable to that of conventional laparoscopic radical hysterectomy. Operative time was 120 minutes, and blood loss was 50 mL. ConclusionReduced port laparoscopic radical hysterectomy is technically feasible. Oncologic clearance and functional results are comparable to those of the multiport variant, with good cosmetic results.

Transumbilical single incision laparoscopic cholecystectomy with conventional instruments: A continuing study.

INTRODUCTION:The feasibility of the single incision, multiport transumbilical approach(SILC) for the treatment of symptomatic gallbladder calculus disease has been established.AIMS:The study examines both short and long term morbidity of the SILC approach.MATERIALS AND METHODS:All the 1338 patients were operated by the same surgeon through a transversely placed umbilical incision in the upper third of the umbilicus. Three conventional ports,10,5 and 5 mm were introduced through the same skin incision but through separate transfascial punctures. The instruments were those used for standard laparoscopic cholecystectomy(SLC).Patients with acute cholecystitis and calculous pancreatitis were included,while those with choledocholithiasis were excluded. Results were compared with those of SLC.RESULTS:Forty patients had difficult gall bladders, 214 had acute cholecystitis, and 16 had calculous pancreatitis. The mean operating time was 24.7 mins as compared to 18.4 mins in SLC. Intracorporeal knotting was required in four patients. Conversion to SLC was required in 12 patients. Morrisons pouch drain was left in 3 patients. Injectable analgesics were required in 85% vs 90% (SILC vs SLC) on day 1 and 25% vs 45% on day 2 and infection was seen in 6(0. 45%) patients. Port site hernia was seen in 2 patients. The data was compared with that of SLC and significance calculated by the student ‘t’ test. A p value less than 0.05 was considered as significant.CONCLUSIONS:Trans umbilical SILC gives comparable results to SLC, and is a superior alternative when cosmesis and postoperative pain are considered, but the operative time is significantly more.

Percutaneous nephroscopic management of an isolated giant renal hydatid cyst guided by single‐incision laparoscopy using conventional instruments: The Santosh‐PGI technique

Isolated renal hydatid rarely presents, but when it does occur, it requires surgical treatment. We report our experience with a novel technique involving percutaneous management of a giant renal hydatid cyst with single-incision laparoscopic assistance. First we performed retrograde ureteropyelogram, which did not show any communication between the cyst and the calyceal. A Veress needle was used for pneumoperitoneum. Three conventional laparoscopic trocars used. Under laparoscopic guidance, we punctured the cyst. The scolicidal solution used was 10% povidone-iodine. The endocyst was removed under vision with grasping forceps through the nephroscope. A Portex drain was placed into the cyst cavity. Percutaneous aspiration and instillation of scolicidal agents followed by re-aspiration have been previously reported. This is an attractive procedure because of its acceptable success rates and reduced morbidity. In our case, simple aspiration of the cyst would not have been successful because the cyst was full of daughter cysts. Also, a blind percutaneous puncture of the cyst and dilatation could have perforated the colon or the mesocolon, which is often wrapped over the surface of such giant cysts thereby making laparoscopic guidance and mobilization of the colon imperative. We devised this unique treatment method for this patient involving three conventional ports at a single umbilical site. We believe this is the first reported case of its kind in the world. Not only this technique is minimally invasive, it is also cost-effective, as only conventional laparoscopic ports and instruments are used during the procedure.

A 3.1 GB/s, 8 Kb, ZERO PRECHARGE, PIPELINED, HIGHLY STABLE 2-PORT 8T SRAM DESIGN IN 65 nm

As the supply voltage is reducing with feature size, SRAM cell design is going through severe stability issues. The issue becomes worse due to increased variability in below sub-100 nm technology. In this paper, we present a highly stable 2-port 8T SRAM cell for high speed application in 65 nm technology. The proposed design provides high stability under simultaneous read/write disturbed access without reducing the I cell . The cell characteristic is extensively examined under random variation. The dynamic read noise margin is improved by 95% over conventional dual port SRAM. The zero-precharge sensing and virtual ground scheme reduce read path leakage current by 95% over conventional high precharge 2-port SRAM cell. The cell current is improved by 52% over conventional design. Finally, an 8 Kb bit-interleaved 2-stage pipelined SRAM architecture is presented using proposed cell. The 2-stage pipeline architecture provides data transfer bandwidth of 3.1 GB/s. Area-efficient 2-stage decoder layout helps to avoid pseudo read problem in unselected cells without sacrificing memory access time.

Ramifications of Single-Port Laparoscopic Surgery

Single-port laparoscopic surgery imposes unique psychomotor challenges. We used surgical simulation to define performance differences between surgeons with and without single-port clinical experience and examined whether a short course of training resulted in improved performance. Study participants were assigned to 3 groups: resident group (RES), experienced laparoscopic surgeons with (SP) and without (LAP) prior single-port laparoscopic experience. Participants performed the Fundamentals of Laparoscopic Surgery precision cutting task on a ProMIS trainer through conventional ports or with articulating instruments via a SILS Port (Covidien, Inc). Two iterations of each method were performed. Then, 6 residents performed 10 successive single-port iterations to assess the effect of practice on task performance. The SP group had faster task times for both laparoscopic (P = .0486) and single-port (P = .0238) methods. The LAP group had longer path lengths for the single-port task than for the laparoscopic task (P = .03). The RES group was slower (P = .0019), with longer path length (P = .0010) but with greater smoothness (P = .0186) on the single-port task than the conventional laparoscopic task. Resident performance task time (P = .005) and smoothness (P = .045) improved with successive iterations. Our data show that surgeons with clinical single-port surgery experience perform a simulated single-port surgical task better than inexperienced single-port surgeons. Furthermore, this performance is comparable to that achieved with conventional laparoscopic techniques. Performance of residents declined dramatically when confronted with the challenges of the single-port task but improved with practice. These results suggest a role for lab-based single-port training.

A study on quantitative benefits of port community systems

Port community systems (PCSs) are rapidly being developed in order to enhance the communications between ports and other port related institutions and gain competitive advantage against the world’s leading ports. Most of the literature regarding PCSs development is either a case study or qualitative in nature. To our knowledge, there is not any research focusing on the quantitative benefits of PCSs to support decision-makers for investment decisions. Thus this study aims to develop a simulation model to capture the differences between conventional port logistics business and a conceptual model where a hypothetical PCS is in place. The differences between the existing system and the proposed system are calculated via simulation based on data obtained from Turkish port industry in terms of time and cost reduction. Finally, the data integration requirements are discussed.

Miniports versus standard ports for laparoscopic cholecystectomy

In conventional (standard) port laparoscopic cholecystectomy, four abdominal ports (two of 10 mm diameter and two of 5 mm diameter) are used. Recently, use of smaller ports, miniports, have been reported. To assess the benefits and harms of miniport (defined as ports smaller than the standard ports) laparoscopic cholecystectomy versus standard port laparoscopic cholecystectomy. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until February 2013 to identify randomised clinical trials of relevance to this review. Only randomised clinical trials (irrespective of language, blinding, or publication status) comparing miniport versus standard port laparoscopic cholecystectomy were considered for the review. Two review authors collected the data independently. We analysed the data with both fixed-effect and random-effects models using RevMan analysis. For each outcome we calculated the risk ratio (RR), mean difference (MD), or standardised mean difference (SMD) with 95% confidence intervals (CI). We included 12 trials with 734 patients randomised to miniport laparoscopic cholecystectomy (380 patients) versus standard laparoscopic cholecystectomy (351 patients). Only one trial which included 70 patients was of low risk of bias. Miniport laparoscopic cholecystectomy could be completed successfully in more than 80% of patients in most trials. The remaining patients were mostly converted to standard port laparoscopic cholecystectomy but some were also converted to open cholecystectomy. These patients were included for the outcome conversion to open cholecystectomy but excluded from other outcomes. Accordingly, the results of the other outcomes are on 343 patients in the miniport laparoscopic cholecystectomy group and 351 patients in the standard port laparoscopic cholecystectomy group, and therefore the results have to be interpreted with extreme caution.There was no mortality in the seven trials that reported mortality (0/194 patients in miniport laparoscopic cholecystectomy versus 0/203 patients in standard port laparoscopic cholecystectomy). There were no significant differences between miniport laparoscopic cholecystectomy and standard laparoscopic cholecystectomy in the proportion of patients who developed serious adverse events (eight trials; 460 patients; RR 0.33; 95% CI 0.04 to 3.08) (miniport laparoscopic cholecystectomy: 1/226 (adjusted proportion 0.4%) versus standard laparoscopic cholecystectomy: 3/234 (1.3%); quality of life at 10 days after surgery (one trial; 70 patients; SMD -0.20; 95% CI -0.68 to 0.27); or in whom the laparoscopic operation had to be converted to open cholecystectomy (11 trials; 670 patients; RR 1.23; 95% CI 0.44 to 3.45) (miniport laparoscopic cholecystectomy: 8/351 (adjusted proportion 2.3%) versus standard laparoscopic cholecystectomy 6/319 (1.9%)). Miniport laparoscopic cholecystectomy took five minutes longer to complete than standard laparoscopic cholecystectomy (12 trials; 695 patients; MD 4.91 minutes; 95% CI 2.38 to 7.44). There were no significant differences between miniport laparoscopic cholecystectomy and standard laparoscopic cholecystectomy in the length of hospital stay (six trials; 351 patients; MD -0.00 days; 95% CI -0.12 to 0.11); the time taken to return to activity (one trial; 52 patients; MD 0.00 days; 95% CI -0.31 to 0.31); or in the time taken for the patient to return to work (two trials; 187 patients; MD 0.28 days; 95% CI -0.44 to 0.99) between the groups. There was no significant difference in the cosmesis scores at six months to 12 months after surgery between the two groups (two trials; 152 patients; SMD 0.13; 95% CI -0.19 to 0.46). Miniport laparoscopic cholecystectomy can be completed successfully in more than 80% of patients. There appears to be no advantage of miniport laparoscopic cholecystectomy in terms of decreasing mortality, morbidity, hospital stay, return to activity, return to work, or improving cosmesis. On the other hand, there is a modest increase in operating time after miniport laparoscopic cholecystectomy compared with standard port laparoscopic cholecystectomy and the safety of miniport laparoscopic cholecystectomy is yet to be established. Miniport laparoscopic cholecystectomy cannot be recommended routinely outside well-designed randomised clinical trials. Further trials of low risks of bias and low risks of random errors are necessary.

More With LESS: A Novel Report of Nerve Sparing Radical Hysterectomy Performed Using LESS

Laparoendoscopic single-site surgery (LESS) and natural orifice translumenal endoscopic surgery are now being used in gynecologic oncologic procedures. We used our expertise with LESS to perform nerve-sparing laparoscopic radical hysterectomy. A 45-year-old woman with stage IA2 cervical cancer was referred to us. The biopsy specimen showed grade II invasive keratinizing squamous cell carcinoma. We duplicated the steps of our laparoscopic nerve-sparing radical hysterectomy procedure to perform a nerve-sparing radical hysterectomy via LESS using conventional ports and instruments. Oncologic clearance was comparable to that in conventional laparoscopic radical hysterectomy. Bladder function recovered completely after removal of the Foley catheter. Nerve-sparing laparoscopic radical hysterectomy using fewer ports is technically feasible. The oncologic clearance and functional results are comparable to those in the multiport variant.

Cholecystectomy Conducted with Single-Port Incisionless-Intracorporeal Conventional Equipment-Endoscopic Surgery

As the interest in minimal invasive surgery has turned to single-site access surgery, single-incision laparoscopic surgery (SILS) is becoming popular. Recently limited numbers of pediatric SILS series have been published. SILS needs nonconventional three-lumen ports and articulated working instruments. However, it is possible to perform single-port laparoscopic cholecystectomy using a single conventional port and conventional working instruments. We herein present our preliminary experience with cholecystectomy conducted with single-port incisionless-intracorporeal conventional equipment-endoscopic surgery. During December 2009-October 2012, 27 patients (12 boys, 15 girls) underwent single-port incisionless-intracorporeal conventional equipment-endoscopic cholecystectomy. A 10-mm 0° scope with a parallel eye piece and an integrated 6-mm working channel is inserted through an 11-mm "conventional umbilical port." Conventional working instruments were introduced through the integrated working channel. The fundus of the gallbladder is hung with a transabdominal sling suture. The infundibulum is retracted laterally to expose the triangle of Calot with a second transabdominal sling suture. Then the cystic duct and the artery are dissected and clipped separately. The gallbladder is dissected from the liver bed with monopolar cautery and extracted through the umbilicus. The patients were 5-17 years of age (mean, 10.7±4.6 years). Cholecystectomy was performed through a single port in 23 patients. A second port insertion was necessary in 4 patients. No preoperative or postoperative complications were encountered. Mean operating time was 74.3±13 minutes. Single-port incisionless-intracorporeal conventional equipment-endoscopic cholecystectomy is feasible in pediatric patients with reasonable operating times. It is a safe, cheap, and highly minimal invasive procedure with excellent cosmetic results.

Intragastric Endoscopic Assisted Single Incision Surgery for Gastric Leiomyoma of the Esophagogastric Junction

Single port laparoscopic surgery is becoming an alternative to conventional laparoscopic surgery as a new approach where all the conventional ports are gathered in just one multichannel port through only one incision. Appling this technical development, we have developed a new technique based on an intragastric approach using a single port device assisted by endoscopy (I-EASI: intragastric endoscopic assisted single incision surgery) in order to remove benign gastric lesions and GIST tumors placed in the posterior wall of the stomach or close to the esophagogastric junction or the gastroduodenal junction. We present a patient with a submucosal gastric tumor placed near the esophagogastric junction removed with this new approach.

Single-incisionvsthree-incision laparoscopic cholecystectomy for complicated and uncomplicated acute cholecystitis

To compare the clinical outcome of single-incision laparoscopic cholecystectomy (SILC) and three-incision laparoscopic cholecystectomy (3ILC) for acute cholecystitis. From July 2009 to September 2012, 136 patients underwent SILC or 3ILC for acute cholecystitis at a tertiary referral hospital. One experienced surgeon performed every procedure using 5 or 10 mm 30-degree laparoscopes, straight instruments, and conventional ports. Five patients with perforated gallbladder and diffuse peritonitis and 23 patients with mild acute cholecystitis were excluded. The remaining 108 patients were divided into complicated and uncomplicated groups according to pathologic findings. Patient demography, clinical data, operative results and complications were recorded and analyzed. Fifty patients with gangrenous cholecystitis, gallbladder empyema, or hydrops were classified as the complicated group, and 58 patients with acute cholecystitis were classified as the uncomplicated group. Twenty-three (46.0%) of the patients in the complicated group (n = 50) and 39 (67.2%) of the patients in the uncomplicated group (n = 58) underwent SILC; all others underwent 3ILC. The postoperative length of hospital stay (PLOS) was significantly shorter in the SILC subgroups than the 3ILC subgroups (3.5 ± 1.1 d vs 4.6 ± 1.3 d, P < 0.01 in the complicated group; 2.9 ± 1.1 d vs 3.7 ± 1.4 d, P < 0.05 in the uncomplicated group). The maximum body temperature recorded at day 1 and at day 2 following the procedure was lower in the SILC subgroups, but the difference reached statistical significance only in the uncomplicated group (37.41 ± 0.56 °C vs 37.80 ± 0.72 °C, P < 0.05 on postoperative day 1; 37.10 ± 0.43 °C vs 37.57 ± 0.54 °C, P < 0.01 on postoperative day 2). The operative time, estimated blood loss, postoperative narcotic use, total length of hospital stay, conversion rates, and complication rates were similar in both SILC and 3ILC subgroups. The complicated group had longer operative time (122.2 ± 35.0 min vs 106.6 ± 43.6 min, P < 0.05), longer PLOS (4.1 ± 1.3 d vs 3.2 ± 1.2 d, P < 0.001), and higher conversion rates (36.0% vs 19.0%, P < 0.05) compared with the uncomplicated group. SILC is safe and efficacious for patients with acute cholecystitis. The main benefit is a faster recovery than that achieved with 3ILC.

Conventional laparoscopy vs. single port surgery from a patient’s point of view: influence of demographics and body mass index

Single port surgery (SP) using a transumbilical approach is gaining more popularity, but who is the driving force behind this development: surgeons, industry, or patients? We evaluated patient's perception in conjunction with demographic data and body mass index (BMI) concerning conventional (multiport) and single port laparoscopy. Surgical patients were surveyed preoperatively and demographic data was recorded. Using the example of cholecystectomy, open surgery (OP), conventional laparoscopy (CL), and SP was explained. Participants were asked to rate importance of abstract items using a 5-point Likert scale (1: extremely important; 5: not important at all), decide between CL and SP and give reasons for their decision. One hundred and fifty (79 females, 52.7%) patients were surveyed. One hundred and six (70.7%) would prefer SP. Abstract items such as complications (1.29 ± 0.835) and surgeon's experience (1.23 ± 0.673) were rated higher than cosmesis (2.64 ± 1.398), length of hospital stay (2.13 ± 1.190), or cost of hospitalization (3.06 ± 1.428). Educational status and experience with prior surgery had no influence on decision making but especially younger patients more often decide in favor of SP (p = 0.007). In addition, more females (p = 0.254) and obese (p = 0.214) patients would opt for SP without reaching statistical significance. Superior cosmesis and reduced postoperative pain were the main arguments. However, only 11.1% of obese patients stated that cosmesis is a reasonable argument to favor SP whereas 56.4% of patients with a normal weight did (p < 0.001). The majority of patients surveyed would prefer SP because of potential benefits such as superior cosmesis and reduced postoperative pain. Prior surgery and educational status had no influence on decision making whereas slightly more female and obese and especially younger patients are prone to SP.

Comparative Usability Testing of Conventional and Single Incision Laparoscopic Surgery Devices

The objective was to perform competitive usability testing to assess the user experience of conventional laparoscopic and laparoendoscopic single-site surgery (LESS) devices. Recent advancements in single-incision instrumentation have created more interest in and usage of LESS. However, neither LESS nor its novel multichannel access devices have been thoroughly studied. Using a simulation test bed and standardized laparoscopic surgery task, the user experience of three commercially available LESS devices was compared to conventional laparoscopic ports based on time on task, errors, task success, and perceived ease of use. There were no significant differences between devices for time on task, errors, or task success (p > .05). For all devices, there were significantly more recoverable than unrecoverable errors, and errors occurred more frequently during the second phase of the task when the dominant hand was more active (p < .0001). Conventional laparoscopy was rated as easier to use than were the LESS devices (p < .01). Device performance of a basic laparoscopic task was similar in both conventional laparoscopy and LESS. Each of the LESS devices facilitated efficient and accurate aiming and grasping movements compared to conventional laparoscopy. Further investigation of human factors and ergonomics of LESS is needed to further develop, evaluate, and refine single-site surgery technologies to create a user experience equivalent to conventional laparoscopy. Competitive usability testing of medical devices yields objective performance data that can be used to inform purchase decisions and future device design improvements.

Totally implantable venous power ports of the forearm and the chest: initial clinical experience with port devices approved for high-pressure injections

To evaluate the technical success, clinical outcome and safety of percutaneously placed totally implantable venous power ports (TIVPPs) approved for high-pressure injections, and to analyse their value for arterial phase CT scans. Retrospectively, we identified 204 patients who underwent TIVPP implantation in the forearm (n=152) or chest (n=52) between November 2009 and May 2011. Implantation via an upper arm (forearm port, FP) or subclavian vein (chest port, CP) was performed under sonographic and fluoroscopic guidance. Complications were evaluated following the standards of the Society of Interventional Radiology. Power injections via TIVPPs were analysed, focusing on adequate functioning and catheter's tip location after injection. Feasibility of automatic bolus triggering, peak injection pressure and arterial phase aortic enhancement were evaluated and compared with 50 patients who had had power injections via classic peripheral cannulas. Technical success was 100%. Procedure-related complications were not observed. Catheter-related thrombosis was diagnosed in 15 of 152 FPs (9.9%, 0.02/100 catheter days) and in 1 of 52 CPs (1.9%, 0.002/100 catheter days) (p<0.05). Infectious complications were diagnosed in 9 of 152 FPs (5.9%, 0.014/100 catheter days) and in 2 of 52 CPs (3.8%, 0.003/100 catheter days) (p>0.05). Arterial bolus triggering succeeded in all attempts; the mean injection pressure was 213.8 psi. Aortic enhancement did not significantly differ between injections via cannulas and TIVPPs (p>0.05). TIVPPs can be implanted with high technical success rates, and are associated with low rates of complications if implanted with sonographic and fluoroscopic guidance. Power injections via TIVPPs are safe and result in satisfying arterial contrast. Conventional ports should be replaced by TIVPPs.

One-port (uniportal) video-assisted thoracic surgical resections—A clear advance

One-port (uniportal) video-assisted thoracic surgery (VATS) consists of approaching an intrathoracic target lesion through a sagittal, craniocaudal plane through 1 single-port incision. The use of articulating instruments inserted parallel to the videothoracoscope enables the surgeon to mimic inside the chest the maneuvers that are usually performed during open surgery. Through this VATS approach, several thoracic conditions can be addressed, including lung cancer in selected patients. Unlike conventional, 3-port VATS, the uniportal VATS technique enables the surgeon to bring the operative fulcrum inside the chest when the target lunge lesion is approached through a sagittal plan, thanks to articulating instruments. Uniportal wedge VATS resections of peripheral nodules can help in solving diagnostic dilemmas, be of therapeutic benefit, and provide tissue for biomolecular studies.

Surgical Stress Response and Clinical Outcomes of Single Port Laparoscopic Cholecystectomy: Prospective Nonrandomized Study

The levels of interleukin-6 (IL-6) are proportionate to injury; it is the most commonly used quantitative marker in surgical studies. Cytokines and the acute-phase response play an important role in controlling the human immune system. The objective of this study was to compare the systemic acute cytokine response and clinical outcomes of conventional laparoscopic and single port laparoscopic cholecystectomy. We compared patients who underwent single port laparoscopic cholecystectomy (the single port group) with patients who underwent conventional laparoscopic cholecystectomy (the conventional group) according to the clinical variables, IL-6, leukocyte subpopulations, and visual analog scale (VAS) pain score. The mean age in the single port group was significantly younger (P = 0.010) and the mean operation time in the conventional group was significantly shorter (P = 0.002). Postoperative 4-hour VAS pain score was slightly worse in the single port laparoscopic cholecystectomy group, but was not significantly different. We found no difference in clinical outcomes, the level of serum IL-6, C-reactive protein, leukocyte subpopulations, and complications between the two groups. Stress response in single port laparoscopic cholecystectomy is equal to conventional surgery. Postoperative 4-hour VAS pain score was slightly worse and the operation time is significantly longer in the single port laparoscopic cholecystectomy group.

Sliding-Mode Antisway Control of an Offshore Container Crane

In this paper, a sliding-mode control for an offshore container crane is discussed. The offshore container crane is used to load/unload containers between a huge container ship (called the “mother ship”) and a smaller ship (called the “mobile harbor”), on which the crane is installed. The purpose of the mobile harbor is to load/unload containers in the open sea and transport them to shallower water where they can be offloaded at existing conventional ports, thereby obviating the need for expansive and expensive new facilities. The load/unload control objective is to suppress the pendulum motion (i.e., “sway”) of the load in the presence of the wave- and wind-induced movements (heave, roll, and pitch) of the mobile harbor. A new mechanism for lateral sway control, therefore, is proposed as well. A sliding surface is designed in such a way that the longitudinal sway of the load is incorporated with the trolley dynamics. The asymptotic stability of the closed-loop system is guaranteed by a control law derived for the purpose. The proposed new mechanism can suppress lateral sway, which functionality is not possible with conventional cranes. Simulation results are provided.

직접분사식 가솔린 엔진의 분사전략 변경 및 EGR 적용을 통한 배기저감에 관한 연구

Nowadays, automobile manufacturers are focusing on the reduction of exhaust-gas emissions because of the harmful effects on humans and the environment, such as global warming by greenhouse gases. Gasoline direct injection (GDI) combustion is a promising technology that can improve fuel economy significantly compared to conventional port fuel injection (PFI) gasoline engines. In the present study, ultra-lean combustion with an excess air ratio of over 2.0 is realized with a spray-guided-type GDI combustion system, so that the fuel consumption is improved by about 13%. The level of exhaust-gas emissions and the operation performance with the multiple injection strategy and exhaust-gas recirculation (EGR) are examined in comparison with the emission regulations and from the point of view of commercialization.